If it's retirement income then I'd stick with the cheapest renovation possible improving the property and increasing the value a lot of times landscaping and or grounds work done improves the visual there by the perceived value and that can be done while your father lives there. 

@Orlando Paz - is the floor where the water shows-up above or below ground?

I guess at least she's taking public transit and not running her car into the ground and spending a fortune on gas.

On the positive side, maybe I can help "on the ground" here if you need someone to check out a place.

Of course nothing can replace having boots on the grounds, but her book is a great way to get the lay of the land.

Does anyone have any ideas for a cheap, potentially DIY solution for a ground cover or pavement?

I always consider from ground zero to "I can breath easy" should take about 5 years on your first go round.

Prior to that, we were stuck with the high cost carriers due to teenager driving records (even though they were grounded from driving...).  

Then you do the records searches and on the ground research to see if the whole story is consistent.

At that point, after making a rigorous and ground assessment of the two models, if the returns for development exceed purchase of existing, you pick that one.