Now we need to give her rent increase notice, can we increase her rent based on $650?

I looked at New London and think it's a fantastic town, probably going to see increases in value IMHO: its got great "bones" as a city, is starting to "urbanify" (trendy places starting to open) but it's way behind the curve, and it seems to me the hipsters there are still young and haven't started having kids/figuring out how to make the city work with kids--so prices are dirt cheap.

You can easily be more or less involved, and whichever you choose will significantly influence your ROI.

I not only help prevent a foreclosure which ruins your credit, I increase their credit by paying off their mortgage of a house they (more often than not) no longer want.

My attorney advised that I could put up a non-refundable option fee for maybe $100 - $500 dollars for a period of time that goes by and then increase for each # of days that goes by in the contract, so for instance:(Option Fee - not Earnest Money)$500 give to seller 3 days after contract is signed.If close hasn't happened within 15 days, give them another $500.If close hasn't happened within another 15 days, give them another $500. 

Tenants tend to think “automatic massive rent increase” when they hear a property is for sale.

A lot of the increases in market value and cash flow were earned through sweat equity and a lot of hands-on-work.

If she finish up the garage (which will increase the property value thus higher property tax), let's say maybe the rent can be increased to, say, $5500/mo.

So I bought a property in 2017 and the previous owner held it for 20 years my property taxes increased about $1,400 a year for that property.

Couple that with an increase in rent that im sure you would implement a few times within the next decade, I think the longer you can hold onto it the better.