I would make two 4x20' boxes with a 2' path down the middle. 200 square feet isn't alot so you'll want to maximize bed area versus paths. Making 20' long boxes is more problematic, but I would be trying hard to not waste planting space. This is assuming that if you do this you will still have access to the outside edges, but I don't really know that. If you don't, then you would have to do all of the bed maintenance from the center, which you may or may not find acceptable.

With my beds I found I can capitalize on the aisle between the beds. My garden gets a lot of light though and I am not doing that "across the board" ....last bed has a piece of goat fence over the top and has small watermelons--but it would work for butternuts etc. I am doing more trellising as I go along....still have to be careful about light.

We built beds that are 3 x 8 inside - I know 4 is recommended but we used plans. Came up with the tops ourselves and they are giving all kinds of possibilities for trellising, and covering (like using shade cloth). I have had more sun than I bargained for and found on really hot days hanging shade cloth over some of the plants is not a bad thing.

Honestly, we made our aisles big enough for a garden cart but I think they are wider than we needed and we could have gained some space by tightening up. 2 feet makes sense. figure out how much you need to comfortably access the inside of the bed.

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jocoyn your garden looks beautiful!

What plans did you use...how high are your beds and materials used?

More pictures please?

3' is a good width, IMO. I can't really get to the middle of a 4' bed, and I'm too old and rickety to be trying to balance on a 2x6 or 2x8 "bridge" to get in there.

When I was younger I thought an 18" path between beds was plenty. I have a new outlook these days though, LOL!