Sell rental now or spend the money to fix plumbing?

[Jack B.]

I have a house I bought with cash just over 6 years ago, living in it for 2.5 years then renting it out for about 4 years. Right now sitting vacant though I have a tenant ready to move in. Freshly painted, etc. I make about 10K after expenses just on cash flow. Trouble is, the house is 75 years old and has galvanized plumbing, old wiring, etc. The water flow in the bathroom became an issue recently. I got the bathroom sink working just by taking it apart and putting it back together but the shower get's no hot water since about two weeks ago. Two plumbers showed up and took the shower apart and told me that I have to replace the pipes. Minimum cost for just hot water line is 1K. To do the whole house is 5K. House also needs a new roof, exterior trim paint, etc. Interior paint and flooring is fine and new. 

The house has more than doubled in value. I would only pay capital gains tax on one year since only one year is outside the 2/5 year rule. I also made just under what I paid for the house off of rents. I could pay to fix it up but it's an old house in a not so great area, an hour from where I live and more and more things will become an issue on this old house as time goes on. It was my first house and has sentimental value, since I paid cash for it when I was in my mid twenties, but holding onto it has major capex payments coming. 

If I rent it for a year, I can cover the roof, plumbing, etc. with this years rent alone. But that's assuming they don't trash it like the last tenants did, where I had to replace doors, paint, etc. 

Question is, do I sell or keep? It's on a busy street and I would not buy it again...I keep it largely as a fall back position since it's paid off. If I had too, I could move back into it in hard times and minimize living expenses. But I could also use the money to buy a paid off house in another part of the country if I ever needed to do that. I could also use the money to pay off a more desirable property I currently rent out but plan on moving back into. I'm thinking I either A) sell via 1031 and roll the money as a DP into another house B) sell outright and pay the 1 year of capital gains tax and depreciation recapture and reinvest the money in a REIT fund or C) Eat the plumbing cost for now to rent it out again and fix the roof this summer.