Great Falls denizens . . .

I'm going to be in Great Falls for a week. Is there any singletrack that could be done as an after work ride (say, within an hour or so of town)? I used to live there a decade ago but was a lost soul (lots of skis, but no bike) so I wasn't plugged into local trails. I'm thinking there must be somethin in the Highwoods and/or Little Belts. Maybe even the front range (Augusta or Choteau area)? What about down by the river--is there any dirt there where I can at least work on some tech stuff? Finally, if such a thing exists, will it be rideable by the week of 16 - 20 May?

Thanks for any advice,
Fischman