Jan I installed a Fantastic Fan on my trailer on my own and it *really* wasnt hard, Lots of threads here on the topic.
Re the layout 4 Scamp which I have. A few thoughts on it. First off I *love* all the extra counter space you do not get with a side dinette layout, dont think I would be as happy with less counter space. The bunks are very nice to have if you have extra guest travel with you. The tongue weight
of a layout 4 is normally lighter than the front bath version if that is of any concern to you.
Downside of Layout 4 as you have indicated is when the bed is down you don't have a separate eating area. Thats something my perfect future trailer will have but having said that I have used my set for 6 years with at least a 100 or more days of camping a year leaving the bed down all the time and have learned its really not hard to live with at all. I have a small compact table that fits under the awning
and provides a nice dry spot to eat even in bad weather. If on the road and only doing fast stop over with no outside set up, then sitting on the edge of the bed and using the kitchen counter as a table works, as does using lap trays while sitting on the front couch. After all you are camping and doesnt that mean ruff'n it just a bit ;-)
I have looked at a lot of the mods both in person and in photos people have made to the layout 4 in making a custom front dinette but having the side bathroom wall up front and sticking out as far as it does, presents some big design challenges to allow someone to sit on the passenger side. It also involves a lot of fiberglass work and carpentry skills to make the mode look as if it belongs in the trailer - something I dont have and with all due respect to some that have done the mod, it would appear some others apparently haven't either and as mentioned the resulting modification may actually take away from the resale value of the trailer.
Have you looked at the Escape 17' Plan B
? Those come up on the used market from time to time even in the US.