My plan is to tackle what I can, and hire out the tough parts. 

They should also not be deterred and have a game plan to tackle that as that is their job.  

Sealing limestone from the inside can create more issues down the road because the limestone leaks naturally and water will become trapped between the limestone and whatever you put on it and the sealant will start to fall off or leak.It's better to tackle the water issue from the outside: Sealing the walls from the outside (lots of digging), making sure water drains away from the house when it rains, proper gutter systems that lead the rain water away from the flower beds.Sometimes you also have to install a sump system.

I KNEW that property was worth in its current condition 100K EASILY but I told him I would have to pass and only ended up buying the other house in the not as great area because I was scared about the overall condition of the first house and I didn't know what other huge problems might have been lurking that I wouldn't have been financially prepared to tackle during the renovation.

What're some other thoughts on how to tackle this?

Make calls on your lunch break, wake up early to tackle tasks you need complete.

This may break down into the following BIG PICTURE steps:Do the front end loading, CAD plans, get secure financing lined up (if you can)Tackle the higher risk construction parts FIRST including from what you've described, the roof repair, the joists and other structural stuff. 

The shortened link tackles the issue of providing an easy way for a person to pull up the property on their smartphone while minimizing the amount of work on the user's part. 

Honestly this is something I wouldn't tackle myself.

I'm going to tackle the floor, I've sanded it down and will be applying a light stain.