Any structure over the fifth (like pole barn) will certainly extend it's trouble free life. Roofs, caulking, rusting screws, nails and staples in fifths deteriorate with age, UV from sun, hot and cold and moisture in the air. Alpha is one of the better units but even those after few years will require some maintenence and repairs.
Quality control in RV industry ranges from OK, to so-so, to mostly atrocious. These pictures were taken on brand new units on dealers' lots.
Fancy ceiling cover by the air conditioner vent (upscale unit).
Wood trim, they couldn't cut it straight, vertical corner piece missing (cheap unit)
Wiring (really upscale unit), but who crawls in there to see this.
You really have to know what you are looking for and I got "caught" once.
We bought a brand new unit from Kropf, wood construction screwed and stapled but also glued in all places where two pieces of wood came together.
We dragged it all over the country for 10 years with no problems whatsoever, sold it to our friends, they used it for 15 years, replaced the black water tank and one window (that's it!).
Then, I bought this piece of crap, wood construction, staple happy construction. (Getting ready to take it to Florida)
Roof leaked, water system leaked, cabinets fell apart, microwave fell off, staples rusted and wood separated all over, etc., etc. Got totaled after about 6 years on the road, was very happy to see it on the hook going to the junk yard.
That was the unit that got me really looking at the RV industry and what they produce and crawling into the places the dealers and manufactures don't want you go into and look.