Just a couple quick things.... Yes, 40' will fit in public parks but it gets iffy with anything bigger. If you want to stay in public parks - national/state forest campgrounds, state parks, etc. don't concentrate so much on the side deck. These types of parks have trees which can't be moved to accommodate your deck; many times an awning won't work. We purposely bought our 40' MH with only 2 slides and they both had to be on the same side so it would be easier to fit inbetween trees. Public parks are our first choice.
A 40' MH and a small towed vehicle (Jeep in our case) is much easier to park on a given site than a 40' 5th wheel and big truck.
We full-timed 8 years in a 33' 5th wheel and 8 years in a 40' MH and traveled constantly, including Alaska. We were very comfortable in both so size doesn't always matter. The reason we switched to a MH was because friends got us interested in Jeeping which gave us awesome fun in the West. We also hated driving the big truck around to sitesee.
Also, if you plan to do a lot of dry camping and boondocking (not parking lots) then forget about an all-electric RV and washer/dryer.
Exit plan: definitely keep the money from the sale of your home as your exit plan.
Can't help with t.v. issues - we didn't watch it.
Volunteering is a good cost-saver; we've done it. However, I hope that wouldn't be your only reason for volunteering. You'll get more out of it otherwise.
SW Michigan get snow and cold... we've lived there. It would be rough in winter. Consider renting a small apt. if you need to be there. Then pack up the RV in spring and take off for your adventure. Propane and site rental will probably even out an apt.