The exterior window and entry door installation were all done by a professional company but I decided to do the interior ones myself.

You call a professional painting contractor and ask them to come over for a quote.Its typically around $7000.00 for inside and outside combined painting as well as all the sanding and prep work.More money if they need to scrape popcorn ceilings prior to interior paint.

She is a friend of a friend so I cannot influence her further.  

If it's the HOA, do they have the insurance to cover interior damage to your property if the roof does leak?  

You have a wide variance of potential profit, but if you very rough ballpark of $25k invested leads to $45k profit, and $50k leads to $70k in profit, I would strongly consider only rushing $25k and tastefully do the interior remodel, but leave out high end finishings.

Variable likes this influence long run calculations so fair estimation here has the potential to add great value.

The house will require some exterior (fascias and siding) and interior work (carpets, paint, patching a ceiling hole).

How much of the interior maintenance (light bulbs), and exterior care (lawn mowing), all depends on how you put it in the lease agreement.I hope this helps, let me know if you have a more specific question...though things might be a little different for me due to location.

I can say a full guy and redo in a house such as that (assuming 1600-1800 SF) assuming interior, roof and mechanicals I would probably be in the $80-90k renovation range without paying a GC.

Currently reading Dale Carnegie "How to Win Friends & Influence People.7.