Option 1:
There's only one place to do a straight 20' run that gets sun. It would cut my backyard lawn in half and I'd want the wire low - 2' off the ground or 3' at the most since it would block the view of the woods from my screened porch if it were taller. It wouldn't interfere with walkways and would provide a demarcation for the bee balm that I wanted to plant against the porch anyway.

Option 2:
Another option is to make the trellis in the shape of an L with 10' arms. I could do this one at the 4'-5' height but I'm afraid it would shade out a rectangle of ground that I thought I might want to use for a second raised bed to do flowers or more veggies. Could I incorporate the trellis into the raised bed and just have the trellis running along the east and north sides of the bed?? Maybe the vine wouldn't shade the bed too badly?

Option 3:
A third option is to grow it up one of the two trees that define an entryway into the woods (leading to the fort!) I could mount a support spanning the two trees and train the vines up and across, making a kind of overhead door frame to go into the woods.

Thanks for your consideration. It seems hard to fit in one vine, much less a couple!

Thanks!
Caroline

In looking at your picture you are right that option 2 would partially shade out your bed. I would recommend running the grapes only on the north side of that bed; since the sun will be from the south you will not shade out very much that way. Either just make it 10' or try to make it a bit longer. If the vine is too vigorous for a 10' length you can start pruning it in the summer to reduce the vigor and make it fit. I was growing muscadines in only 3' per vine spacing and found it easy to do with summer pruning (but unfortunately the spot was too shady, something I didn't take careful enough note of at planting time).

The option with the two trees sounds too shady.

Scott