Yeah, getting back to Oshkosh.
Do you monitor 120.7 all the way from 15 miles before Ripon to touchdown?
Or do they give you frequency change at Pickett/Fisk?
Pick up the Arrival ATIS on 125.9.
Yeah I tune in 120.7 a ways out. It lets you know how busy things are. This lets you know how busy things are and if there is something that's stopped up arrivals. There's no point in trying to join the transition if the airport isn't taking arrivals. Go hold somewhere else or land and wait it out.
Once you get to Fisk, they'll tell you to either turn EAST along Fisk road (it's obvious) for 36L/R and told to change to 126.6 or to continue along the railroad tracks for either a base entry into 9 or a right downwind entry to 27 and change to frequency 118.5
Those are the normal and most orderly configurations. On a rare occasion they may have to use 18. keep an ear out as to what they want you to do, they can either send you up the tracks to a right base or turn you east to make a left downwind entry. It's less common that they do this.
All these various things are in the NOTAM however.