First off, what kind of grass do you have, or where do you live? How much sun does your lawn get (not the pachysandra parts)?
Your plan is pretty good, and if you live in the northern half of the country you should wait till late summer/early fall to seed your lawn. Here's what I would do.
1. Soil test (www.loganlabs.com). Turn around is about a week. Once the results come back, you can decide if you need lime and or other amendments.
2. Put down a preemergent herbicide. Dimension would be a good choice.
3. Spot spray weeds with a selective herbicide like Weed B Gone Max and CCO.
4. Kill moss with Moss Out.
5. Fertilzing should be done in late spring (cool season grasses).
6. In summer you won't be doing much except deciding if you want to overseed or kill everything and renovate.

I won't get into the seeding steps, you have time.

Thanks!
I plan on taking some pics when I get home from work so I can show you all my trouble spots.
I live in Connecticut near the Long Island Sound just north of NYC. I can't tell what type of grass I have, hopefully the pics will help.
The front of the house faces west so the sun hits the back in the morning and reaches the front by afternoon so the whole lawn in general gets good sunlight through the day.

A fellow nutmegger, and in Ffld. county, like myself. When you take pics, if you want your grass identified, you will need to post close ups of the blades.

This is the front yard. Its different grass, weeds and moss. There is a large dirt patch filled with weeds in the front left out of picture and the moss under the Japanese maple on the top right will be tilled and tons of pachysandra planted under it.

This post was edited by Biggreen73 on Mon, Apr 1, 13 at 18:35

This is the backyard. It's got more grass than the front yard. But next you'll see the large moss patch left from an old playground set and this weird weed that I have two patches of.

Anyone know what type of grass this is?

So in the backyard there use to be a playground from the previous owner. It's now a dirt and moss patch. Is the right procedure to rake up the moss and then lay down some Moss Out?

This post was edited by Biggreen73 on Mon, Apr 1, 13 at 18:36

And also in the backyard is two large patches of this stuff.
Any idea what it is and how to get rid of it?

And then this is the even larger dirt and moss area in the backyard that will be tilled up and planted with pachysandra.
Should I use Moss Out on this area? And if so should it be used before or after I rake up the moss and till it?

I would recommend against tilling you yard. You're going to end up with more weeds (bringing them to the surface). I have had success with tilling, then flaming (using propane) after tilling and smoothing with little to no weeds, simply because the heat at 24k BTU made anything at the surface area burst. Granted, that was a small area of about 20x20 (and to note, there are still no weeds and I've never used any sort of herbicide, organic, or otherwise in that area!!!)

Your lawn's going to be a good deal of work when you can just spend the spring/summer doing Roundup and then reseeding in the fall. Won't be pretty... Will suck having a desert for the summer. However, you'll appreciate your patience and perseverance of waiting until August to reseed. Next spring you'll be enjoying your personal fairway with a drink in your hand. Cheers!

Looks like a typical mutt lawn, consisting of a few species of turfgrass. I see some tall fescue, and perennial rye or KBG, maybe both. For broadleaf weeds use something with the active ingredient of 2,4 D. Weed B Gone Max contains that, and works well. For certain weeds you need more triclopyr. Weed B Gone Clover Chickweed and Oxalis killer is mostly triclopyr and you can mix it with the Max. I would spray the moss first with Moss Out before raking. Moss Out works very fast, often the moss will turn black in a few hours. Raking living moss increases its spread. Dead moss will add organic matter to your lawn and not require raking. In a lawn like you have starting from scratch might be the best option. It's a little more work, but the results are much better. Again you have some time to decide if you want to kill it all and seed or just overseed, but the sooner you decide the better.

Thanks for the help.
I agree, killing everything and starting from scratch would be the best overall option. But, my wife is against us having a desert for a lawn and wants me to try to tackle it first with some weed and moss killer.
As soon as I get my soil test results I'm going to get at it.

Looks like my plan is to treat with lime if needed or anything else depending on the soil test.
Then hit it with moss out, pre emergent with Dimension and a mix of Weed B Gone Max and Chickweed, Clover and Oxalis killer.
Can all these weed killers be applied at the same time?

Then in late spring hit with a feed and weed.
And then aerate and seed in the beginning of the fall and one last fertilizer in the late fall.

You don't have to wait for the soil test results to apply Moss Out, or the herbicides. Moss out is just an iron solution, not really a herbicide. Dimension and the Weed B Gones can go down together but Dimension is granular and needs to be watered in (you can get Dimension liquid, but granular is easier to use), and the Weed B Gones are liquids and need to dry. So space those two out a day apart. Late spring fertilizer is fine, don't use Weed and Feed, they don't really work all that well and the timing doesn't make a lot of sense. Kill weeds with the above herbicides, and fertilize separately. Aeration is a good idea only if your soil is compacted. If that is the case, then it might not be a bad idea to do that first, like now, before you put your Dimension down, as aerating can bring up dormant weed seeds. Most yard soils aren't manually compacted, but suffer from a cation imbalance that makes the soil very tight. Your soil test will reveal that.

Honestly I would just mow it short and do nothing until the fall when you zap the whole yard with Roundup. Unless you are going to use KGB exclusively you're only talking 1-2 weeks MAX before you have a nice bed of green (to appease the wife). Much better results and much less work/$$$ than what you plan to do.

Just live with a somewhat bad looking lawn for the spring/summer (honestly if you mow short all the bad spots will fill in with weeds and grass and not look horrible from a moderate distance). Think of all the extra time you'll have to do other home projects!

That fence looks pretty awful. :) Since you don't have to worry about harming the grass why not power-wash and stain!

When I first moved into my house (10 years ago now) my backyard was a beautiful green, dense, lush.....mess of clover and broadleaf weeds. When cut to 1.5" or so unless you were looking at the individual blades I constantly got praise for my "lawn". For years I tried this or that product not willing to go and Roundup it and start from scratch and a lot of time and money was wasted. I ended up successfully renovating it to fescue but it was a TON of work.

In hindsight I should have either stuck with the weeds and mowed low, or completely started from scratch (my recommendation for you).