Smitty - My original plan was to do that just without the bars. In hindsight, it was really east to cut the rear section away so if you are set on having a similar porch, remove the windows and cut the pillars out but leave the bottom. If you dont like it, it is easy enough to remove the rest but would be very hard to put it back in place. The nice thing about that is you have a porch and a quasi pickup truck bed to keep items in while you travel. If you did it this way you wouldnt have to fool with the tail and brake lights either and would also have the half emergency door as a tailgate.
BTW, I assume you bought the Carpenter bus, looks like a great platform to work with. Just dont set a deadline to finish it by, you will be frustrated the day you pass it and the bus isnt complete. Take your time and enjoy the build, it is very rewarding.
Here is my original concept with (I think) your porch idea. Really wanted this Freightliner. Had the crappy 3126 with blowby and thought we would pick it up cheap but it went for $4500 at auction with 200k and a ton of smoke out of the slobber tube.