Son lives in the Inland Empire and asked if I would be willing to go to the house prior to meeting him and cover the roof with plastic.

Are there any reputable lenders today allowing 80/20 combined loans? 

Again if I can help these folks in any way I want to not only for them but also for my personal experience and reputation.    

Can anyone suggest a reputable property management company located in the King of Prussia area? 

DAP also makes a clear elastromeric sealant that is available at the big boxes which can be used  in a pinch.....we just prefer the other.Don't let roofers use plastic boots....you have to check them on this....use the aluminum based boots for a longer solution and run a bead of sealant around the upper edge of the rubber grommet that seals against the vent pipe.  

I loaned $20k to a guy last year I'd never met and didn't bother to record the deed I got because someone I trust said I could trust him (and said he'd pay me back if that guy didn't)  Reputation goes a long way in this biz when you've been at it a while.Anyway, things vary from state to state on doing it, but its essentially just two documents, a note outlining the terms of the loan and a security instrument (security deed, deed of trust) that encumbers the property with the note so you cant sell it without paying them. 

Are there any reputable lenders today allowing 80/20 combined loans?

If you get a reputation for wasting everybody's time, nobody is going to want to work with you.

 @Elizabeth Colegrove  Is it smart to find a bank that does portfolio lending as well but first exhaust the conventional methods, build a reputation then work my way up to the lending managerOrFind any bank that will finance my first deal, try and repeat the process a few times and when I need a portfolio lender just start searching when I cross that bridge.

While I was interested, (not for a profit, however) my instincts told me to be careful and not rush into things as my reputation was at stake if his data or service was questionable.