I've done the trip a number of times as I live in Calgary. Although, not recently. From what I hear, the shoulders have not been kept up so while paved, they can be a bit rough.

Best bet is to park your transportation in either Banff or Jasper, ride to the other location and then back again.

You do have to carry enough food for how ever many days you plan to ride between the two major towns. There are a couple of spots you can stop and get food but they are are expensive.

Weather can be anywhere from the high 20s (and even into the 30s), made "worse" by the high elevation (you'll burn if you aren't protected) to the freezing mark. You can hit beautiful blue days or days where the clouds are so low you can't tell there are mountains. I've hit snow on the August long weekend - big fluffy flakes that hurt as you descent down a 8 to 10% grade, taking the full traffic lane and passing vehicles.

No trucks to speak of but you will find tour buses and "monsterbagos" driven by people who normally drive a tiny compact car. But, the shoulders are very wide so generally no problems.

As someone else said, later in June through August are the best times with the best chance of hitting nicer weather. But, it WILL be cool in the evening (cold for some people).

There are enough Youth Hostels along the IFP (Ice Fields Parkway) that you can easily stay in one every night. They are warmer, have cooking facilities and fireplaces. Plus, the one at Mosquito Creek has a SAUNA and a freshwater (glacial fed) stream within running distanc to the sauna. You can do the "heat up and quickly cool down" thing.

Be aware that you are in a nature preserve and take necessary precautions (ensure that whatever you have in your tent has NEVER come in contact with food, cosmetics or anything else that might smell appealing) and store all such items in the bear lockers provided at every campsite. Staying in hostels mitigates this as they are all wood so critters, even large ones, can't really get in.

It is more than worth the trip though.