It's a steep barrier to entry into this particular group, no doubt, but the people that are really motivated hit the ground running and make up the investment in the first few months.  

Some items are full stop improvements (think structural things like a roof or foundation, which are inherent to the property being habitable), and others are quite clearly repairs (like fixing something broken).

I ended up getting everything done (complete interior remodel, new finished basement and new roof) within 6 years.  

This home is in an association, so I don't have to cover roof/siding/exterior in any way, but water softener, furnace, appliances etc. are obviously all on me to maintain.

As a last resort - Home Advisor - but their prices can be steep at times.

Here in Denver, they are being built with completely separate roofs, landscaping, garages, etc., so that might be something to look for.Are you going to rent out rooms to house hack it then? 

He said my wall heaters aren't vented (they are, and through the roof, you can plainly see the vents from the outside of the house).

The advantage in multifamily, is if you need a new roof, you only have to deal with one roof, one mortgage, one sewer system as opposed to 10 roofs, 10 mortgages and 10 sewers and so forth.

I checked under the trailer this past summer, the furnace works, has w/d hoop ups, hot water heater installed a couple years ago and has a solid roof.

Ideally you would find a company that has everything under one roof.