I spent a couple years as a taxi fleet mechanic and a third of that fleet was 01-07 Caravans and Town & Countries. Aside from transmissions shitting in part or in whole (solenoid valve packs) and rack and pinions leaking as fast as we could change them, they're also notable for intake gasket leaks, oil pan gasket leaks, brake pads were generally only good for around 35K, tie rod longevity was hit & miss, alternator and/or decoupler failures, the power steering reservoirs as somebody else mentioned, water pump failures, occasionally rusted through coolant pipes from the engine to the radiator and always rusted through pipes for auxiliary rear heat (I can't remember for certain, but they may have finally started installing aluminum lines for the rear heaters starting in 06 which would eliminate that complaint.), harmonic balancers wobbling and causing chronic belt chirps, the occasional fuel pump cracking its own housing on top the tank, sway bar links and bushings wearing out hard, rust and rot in the rear quarter panels, plenty of various evap component failures, engine mounts failing, (albeit I saw this much less in non fleet minivans), and whatever else I've forgotten since. I left the fleet mechanic life and joined the service repair side a few years ago. I loved having those show up in my bay because they were just as bad in daily driver form from my customers. To put it shortly, they were job security.
It's not to say entirely you shouldn't consider buying this one though. 80K sounds enticing as long as the price is right. That kind of mileage suggests the van has been owned by somebody who is older and would never beat on it. If they can share any service records showing transmission fluid maintenance, or good maintenance in general, I might be enticed to buy it. I would have it inspected no matter what before any commitment to buy. But, if I did commit to buy, I'd buy it on the notion that I'm going to put 50,000 more rounds on the odometer and then it gets traded in no matter what. You can't forget that even though the mileage is low, the van is still 13 years old. Depending on climate and how the vehicle is stored when not being driven, it can still have rust and rot and mechanical & electrical gremlins waiting to cost you a lot of money. Some of those things I mentioned will hit you along the way. Hopefully, it would just be some of the little things.
Whatever you decide or did decide to do, good luck.
No matter how much technology changes, there still isn't much that can't be solved with the sensible and practical application of a bigger hammer.