The first thing I do to set up a new setting outside of the settlement is establish native nonhumans in a region. Ambivalent if not allies to the human nation so they can be sough for aid. Then a few CRs later, come demanding aid back against something worse. Elves work if they're near woods. Dwarves if they're near mountains. If there's a swamp nearby I'd recommend Lizardfolk as some kind of spice. Consider pacifying but not killing a clan of giants on one excursion so they can also come back on your town's side.
With your setup keep the destruction fresh. From side effect of fights, to intentional arson, accidental arson, earthquake the owner blames on the party, I'm sure you gave thoughts on this, but it'll make recapping more fun to players coming in on the 8th session to hear the list of damaging/destroying events for the bar. Have at least one destruction be caused by teetotalers and puritans that have beef with the morals of the party. The more petty the better for comedy's sake.
Similarly have the rebuilding/repayment change too, but not as often. Maybe after a third total loss have the owner suggest that the workforce that's been repairing the bar is occupied, and insist the PCs request the commoners or the local allied peoples repay the PC's favor for with a Bar Raising. If there's a bard: give them a Lyre of Building and have the Tavernkeeper nitpick the construction, forcing them to start building the place over again, running up debt in materials
I'd probably flip the script around level 8 or 10. Have the players get magical loot that could pay all the debt of rebuilding the bar off, but not have anyone in town that's able or interested in buying it. Wind up with the town getting destroyed in the course of the game and after all's said and done have the Tavern Keeper demanding the Instant Fortress they pillaged to set a new bar up in a new town. With that assuring the bar won't fall down from two drunks throwing chairs again.