Concrete:  $75 a yard installedBrick:  $.50 per brick installedpainting:  $100-150 a room with trimexterior painting: $1800-$2500new hvac : $2300new window:  $100-$150 for standard sizes x 2 for installdrywall : $12-$18 a sheet finished (depends on finish level and size of sheets)tile: $5 a square foot installed (add material cost of between $2 and $10)basic stainless appliance package : $2500hardwood $2 a sq. foot installed $1 a sq foot to refinish (add material cost of $2 to $10)plumbing:  $100 per fixture to install and $100 per fixture rough-inelectrical: priced per outlet and per fixture for both rough-in and installTotal rewire of house:  $3K-$6Kupgrade electrical service:  $800Total replumb of house with pex (no slab): $2K - $5K10x10 set of cabinets no frills:  $2500, about 1 day for a capenter to installcountertops: $1500-2000new roof:  $5K (metal including materials)deck:  $2K-$5Kbulldozer/bocat:  $80 an hourdumptruck:  $1.50 per mileCarpenter:  $35 an hour low end + $10-$15 an hour for helpers. 2 carpenters can frame an entire house in less than a week.  

Some contractors weren't great about writing detailed invoices so in some cases all I have is a large check written to 'roof guy'.So.... question: is there alot of scrutiny from the IRS as to how you determine the basis?

Saratoga is booming right now, but it would be harder for me to penetrate the market since house prices are through the roof.

Many on this board would give their eye teeth to be in your position.If I had this opportunity, I would take full advantage, work my butt off without counting the hours, and learn as many aspects of the business as I could.

Seller has also agreed to a 1yr home warranty and termite treatment as evidence of termites were found during inspection)*roof is old, will need complete tear off when it's time to replace.

Especially if you're getting on the roof!

I had to transfer monies into my rental SP LLC to replace a roof.

I'd probably put a stronger clause in a new agreements about keeping the visible aspects of the property in good shape and enforce that.  

I hope it's not too late to invoke the partner aspect, it allows you to be a lot more demanding in terms of your due diligence, and it allows you to not be the bad guy if you have to turn them down ("I wish I could have helped you but my partner said no and we can't invest any of our money unless we both approve the investment").To your original question, IF you decided to make a loan like this, I would see three options:Unsecured personal loan (weakest/worst/don't do it option)Secured loan - they buy property and you are the lender secured by a mortgage on property (better)Rent-to-own - you buy property and they rent from you with an option to buy (questionable esp w/ family, may be tricky or illegal depending on how structured, etc. and see next point re: owner-occupied)However another aspect is that since this would be an owner-occupied property, there are a ton of consumer protection laws (Dodd-Frank) that apply.

Looking back and knowing what I know now, I would've definitely had a lawyer draw up a contract in regards to ALL aspects of the partnership including dissolution in order to mitigate the risk of ending up in court, spending large amounts of money on lawyers and a great deal of stress.