Id venture to guess that mh from the 70's are not worth jack squat and will need lots of up keep.

By the time they realise it is all going down the toilet it is too late.I strongly advise new investors buy local and manage their own properties until they become callused and hardened toward managing tenants of their own.

Other non-code enforcement issues I look for when doing inspections on my own: change air filter, check to make sure toilets are not running, run water in sinks and check drain pipes for leaks, check for signs of unauthorized pets, check to make sure all windows operate, check all GFCI outlets with a tester and make sure they reset. 

If it is not their fault (ie a tree root has grown through the sewer pipe which is why the toilet keeps backing up or something like that) then I would probably get the problem fixed after the 3rd time it happened.

I have a prospective client in Sunnyside who hired his handywoman to convert an existing garage to a loft-style studio with a composting toilet.

It also has loose/damaged siding, security bars on windows that need to be removed, earth-to-wood contact in the foundation and siding, leaks in sinks, windows that don't stay open, loose toilets.

Roof, hot water tank, furnace, leaky toilets. 

One bathroom just needs work and a new toilet, the other needs to be completely replaced. 

It has been proven to me over many years that is a dark and dangerous road.In our leases, it states that if the maintenance issue (lets use clogged toilet or sewer main) is a result of normal wear/tear or lack of owner maintenance, the charge rightfully belongs to the owner.However, if the tech pulls out a toothbrush or Barney the Dinosaur out of the drain, the full charge belongs to the tenant. 

So they know absolutely jack squat about investing and how to value a deal as a rental property.