Mike

The highest probability of icing is at temperatures around freezing. The potential for ice is a fact of life in the Northeast where I live, but the ability to forecast ice has really improved in the last few years. The best tool I have seen is  http://aviationweather.gov/exp/fip/. Take a look at it every now and then. It can provide a pretty good handle on potential ice you can go over, under, around, or a clear "stay home" message While it won’t help you on your trip, you can get a feel for how icing characteristics vary with altitude and time from it. I have found this forecasting tool to be pretty good.

Given the altitude and range of your IVP and a good weather briefing you will be OK, although you would probably be better off in July or Aug.

Regards

Bruce