You can get a value on the buildings by getting quotes to build them now.
When we were going through the acquisition of our back lot cabin (tear down liability), and 2 car garage (new in 2000) on two lots up the street from their primary cabin so my FIL could have somewhere to store his crap and the boats; we based the max value we'd pay on what the two lots, the septic (recently replaced, up to current code), and the garage were worth. But he still spent more than I though he should because the cabin itself is a liability and should be dozed, but he got caught up in a bid war with another neighbor who wanted the space.
Which brings up another issue: do you have neighbors who want it? I paid more than I would've elsewhere because my land was in direct proximity to the in-law's cabin. We also have a slew of potential buyers should we decide to bail before building our "forever house" out there, so I'm not overly concerned about moving it if we need to.
To throw my numbers down - I'd say your swamp is worth about 28K and your upland around 30, plus two 25K buildings (give or take), and the ponds. So the 120K figure is right in there but might de-value the ponds a bit. But it's a nice place, so I'm with Stu and would expect to see it listed higher, but finding a buyer could be slow. Proximity to St Cloud, and the North metro is a big plus and X-factor at the same time. You might find someone who wants a spot to put a big shed and hang on weekends. Those ponds are money to a guy who wants to drop a line and catch something almost every time.
My buddy wants to know how much? :D