When you look at a property make a list of all major capital expenditures roof hvac etc.

You will need to cover perc tests if needed for each lot and then hire a surveyor to draft the ANR plan for submission to the town, just treat wetlands as sacred Indian burial ground - stay away from them and your costs will be very low.  

In the event my landlord is interested in selling, I was wondering if I could add value in the short term by, say, converting part of the garage and/or covered porch into a bathroom and maybe a bedroom (currently 3 bed 1 bath).

Labor/material are going to be different and need to factor that in4) new roof, new HVAC, new water heater, ac panel, replacing plumbing to PVCThese are very variable, if you are getting this from a licensed guy to do it and unlicensed.. is it a big shop or a local shop doing it, is the GC doing it they will put some money on the top so it will be more money5) framing (creating new bedrooms or baths)I would get all these quoted from a good couple of licensed guys and unlicensed to know your numbers to cents

AND The balance on one statement is < 100 and other not enough to cover the first months rent and deposit.

If the home is 100 yrs old, I'm assuming it's a definite gut which is going to require new plumbing, electrical, heating, cosmetics.I spent about $140K reno on my multi family in the heights on NY ave and there were massive problems with it but it was a gut to 3 units & adding 2 bathrooms, 3 brand new kitchens 4 bathroom reno in total, all new flooring, sheetrock , insulation, framing, doors, electrical, plumbing, paint, parts of roof etc.

What i did not have to do while owning them though was roof plumbing elec appliances stuff like that.. those lasted a good long while..

I would agree with Chris, I would not use debt to cover all costs and then hope to get a good pop on the sale to cover all the debt, payments and still have some in the end to make a profit to do it again.

I've argued for this and the powers-that-be do have a good argument that they are still active just in other ways, how to cover labor and actions during that, etc..

Our goal has always been to bring in enough cash flow to cover ALL of our living expenses.