We have already remodeled  the kitchens, updated plumbing, worked on the septic, insulated the attic, painted, etc.

"Lipstick on a pig" Home Depot remodels don't work anymore.

It should be equity you achieved when doing the remodel. 

I would look for homes to purchase and invest in then remodel and flip them or rent them 

Even large and small businesses with intangible residual services like TV, internet, security, pest control or the local contractor with remodels in process could fall behind on payments revenue contract. 

He has lived here his entire life, and knows the area very well, and he is a general contractor and has been remodeling homes in our area for 20 years.

So for me if I'm budgeting $250,000 on a remodel (with a very detailed line item budget) then I'll add another $50,000 contingency to cover the unknowns.

I'm more familiar with the residential side of RE, being part of many remodels and home projects, but would like to have expertise in both commercial and residential.

I intend to add a closet to the den and make it a 3 bedroom adding value as well as remodel the entire unit.

Then get a GC to give you a tight proposed budget to restore this old beauty back to it's former glory.This sounds like a $200k - $300k remodel at least.