Generally it is a good idea to plant more than one melon vine to increase the number of bees which visit, but Crenshaws should be able to self-pollenize with a little help from insects. Melons may be oddly shaped and undersized if there are few insects and only a few of the seeds inside get pollenized. Do not do any pruning until after melons have set and started growing. Then you can choose those with the nicest shape and take off other fruits to direct energy to the remaining fruits. Four seems like a lot to me unless your plant is very vigorous. This is late in the season for Crenshaws (especially the traditional ones) to be setting fruit. I would probably go for a couple of melons if I were you in hopes of getting ripe ones during warm weather. If it were an earlier melon, I might let a second wave of fruit to form.

Thanks for the info. Greatly appreciated!