Made small improvements like paint, added a huge deck for the apartment over the garage and fixed the small issues that the city had with the property, like removing a strip of pavement that was 1' too wide.  

I saw deferred maintenance issues which were going to cost to repair like new roofs, stairs and decks looming in the near future which would provide no return on investment so decided to just get out.Good luck to you, have fun and learn from this venture.P.S.

Here's an idea we used on our last project to hide the underside of a deck without using lattice, anyone else have any cool ideas?

There are usually flat fees for things like roofing, demo, tanks, pools, decks, and electric, too and those range from maybe $20-500 depending on the town. 

I like Account Closed's suggestion of having parking underneath the perimeter of the building.Stormwater detention can go under the surface parking lot at a cost of about 2-3x traditional BMPs, but that could possibly offset the additional cost of deck parking.

A few of my concerns being:1) You don't have control of how the building on the ground level is being taken care of...2) I'm interested in making the roof of the apartment a deck... if it's structurally sound, would you be allowed to do this if you own the top unit?

  , got it done for 390 per. still high material is about 135 a sq.  23k for an 18 ton bosh C/A got it done for 14k, 11k in labor to build a 16 x 40 deck, I got it done for 4k . 16k is a rip off. 5k to paint all my trim about 400 ft, rip off, got it done for 2500. 16k for my landscaping, two days of work rip off, got it done for 10k   I can go on.

Not enough info and too many variable to have a definitive answer for you, but ... some options (or thoughts):IF it's older construction, you could have: Wide rafter spacing (24" o.c. instead of 18"o.c.) and thinner decking (like 1/4" plywood instead of 1/2" (7/16" really) OSB), so your going to have some waves over time!

Paint, flooring, new back deck, light fixtures, etc.

I'm also wondering if I need to put 6 hot tubs in on the decks each unit has... that will be pricy.