Bob,
Well, reading your post brought two things immediately to mind.
1. A stronghold is a great thing. I wish my PC had one (he's in a 12th-level party now, and the closest we come is standing reservations at the inn!) Story-wise, it gives the PCs someplace to call home, and that's a special thing that can make the campaign much richer. As the DM, it also provides you with plot hooks and a way to drain off the excess money they'll earn now and then. Which brings me to---
2. As another poster said, 125,000gp is a lot of money. If you intend to run a standard game (i.e. using CRs from the Monster Manual as guidelines, etc.) or even a Forgotten Realms-type super-charged campaign, 125,000gp is too much money. You got lucky this time, in that your PCs decided to buy a stronghold. Next time, they might decide that a
Holy Avenger or
Staff of the Magi is a better idea. Remember that 125,000gp is more than the total net worth of a 13th-level PC, by the standard rules.
Please note that
this is not a criticism. I firmly believe that each game is the DM's own, and can follow whatever guidelines he or she wants. But
remember that if you are giving out this kind of gold, the information in the various core books, such as CRs, ELs, and everything else goes out the door, because they'll be calculated for standard characters, and yours will be far more powerful than that. It's not bad or wrong, but you'll need to adjust a lot of stuff to take into account the kind of money your PCs are dealing with.
Bottom line: if you want to run a super, super, super powerful campaign, ignore number 2 entirely. If you want to run a more standard campaign, count yourself lucky that the PCs spent their gold on real estate and make a note in your DM's notes to never, ever give that kind of money out again.
Happy playing.
