I plan to do the trim flooring and painting myself and hire the rest out. 

Paint, floors, bathrooms, general maintenance, landscaping What was the outcome?

For example my simple spruce up would be, renno bathroom, and kitchen, paint, and redo carpet upstairs.But if i think real deep into what I could do to make it a STUNNER then I think, knock down walls, create more open/broken floor plan, add central air, possibly do an addition to add a 3rd bedroom and second bath.So when you could do ANYTHING .. how do you draw the line of what you should do?

I’m not super keen on having long-term tenants in a single-family home in California, but I’m open to advice on that.The house is in decent shape but could use new flooring, a paint job, and potentially heating and/or central AC, as well as blocking/taking out the existing fireplaces (don't love the idea of fireplaces in a rental). 

Quote from @Michael Baum: It is amazing what you can find in thrift stores and the like.This ^^^^ I never bought a new painting/or piece of art.

I watched my parents flip houses since I was little and have always been on job sites or made "pocket money" by doing chores like painting fences or washing kitchen cabinets, which I realize now my parents were putting us to work to build that sweat equity.

   $100k would be tight.A 3/2 -- 3/2 no walls moved;   $90k is possibleA rental rehab;  lipstick, no HVAC or roof, keep everything, paint kitchen cabs and scrub up bathrooms. 

Currently looks like some small cosmetic exterior painting is needed on word parts and windows. 

Painting in the interior saved at least $4k.

Can I ask about your interior paint colors?