I had some ideas also which could be like a hot tub or sauna games (pool,video games, airhockey ETC).

We are adding a barrel sauna and a couple of other things.That's a good idea about the additional holding tanks and the monitor, we will add those.One thing I am a little confused about how to do is when you say:"Someone recommended getting your future pricing in line to capture people looking 3 to 6 months down the road and I agree with them."

Quote from @Jinida Dorsey: I've been reading about and started following BOXABL, the manufactured tiny, portable home "kit" concept.

Too long of a list for a single post, but in short ...Buy in a good location, something architecturally unique if possible (or make it unique through great design), buy great furnishings with an eye toward style to stand out, add a few amenities to stand out (hot tub, sauna, game room, star gazing dome...), and pay for killer photos.In short, bring your A game.

As far as I am concerned, you can only claim residence in your primary residence, so how does tax portability plays a part in all this? 

Now if the building has amenities such as a pool, sauna and workout room then you are actually in a condominium complex and a different animal entirely.I’ve had a few deals go south because of a greedy seller and the lure of the condo-cashout, attempting to sell out for more money than the property is worth.

Mobil homes manufactured off site (usually half's) and can be portable or have fixed foundations.

Quote from @Theresa Harris: He should have a portable AC unit in his bedroom, but if they (the tenant) are causing damages/excessive wear and tear, do not renew their lease. 

More than that IMO is too far.Bonus - my thoughts on your plan.Before I go there let me explain my properties, 3 of my properties have private indoor heated pools, all of my properties have hot tubs, arcades, theater space, etc.. 1 of my properties has a sauna. 2 of them have coffee bars.

Modern design -- preferably led by an interior designer -- plus great amenities like a hot tub, sauna, game room, etc.