Before you go out again, you can check the water levels in the river you plan to tube...as kayakers we live by these levels! It also lists the flood stage for that river so you can judge by that. If you google water trail and your river, you can see a map of the river/creek with launches. We have a few canoe books that detail the pa water trails and give a minimum level for paddling it (something like Paddle PA and PA Canoeing)
Here is a link to the USGS site...there is a map of PA and you can click on the river you want to tube...http://waterdata.usgs.gov/pa/nwis/rt
BTW...If you are near Huntingdon PA, a great tubing river is the Raystown Branch of the Juniata below the Raystown Lake Dam from Corbins Island to the Point. There is always water to run this 4 mile section and there are many put in/take outs along this stretch to shorten the run if you wish.