But on the other hand, it sounds like you're fortunate to have all paying tenants and you might not want to risk rocking that boat.What I can tell you is, the worst possible scenario is actually NOT you raising the rents and your tenants leaving and you having to re-rent the place. 

Really want to avoid anything more than 10% down at worst, but would gladly take 5% with comparable terms.

There is nothing worst than a bad fit.

California has done very well recently, but then again in '08 they were one of the worst hit, and in a down turn a negatively cash flowing investment is the worst place to be.I hope it works out

Like others have said the first year is still the worst due to things missed which should be minimized but after that it should get better.  

Worst case, you use or lawyer to review contracts.

I listened to one of those motivational video/audiotapes that says the worst thing you can do is to set your goal too low and achieve it.   

As other people mentioned, you may be able to patch rather than replace the whole line.Sewer pipe repairs are the worst problem you can have.

This is all “planning for the worst....”

There is no tourism in my town (the worst town to live in Kansas).