OP, we did the ice fields parkway last Canada Day long weekend. We love it up there!
I'm with those in the "let tow/haul mode do its job" club. Just keep an eye on the tranny temp, as ours did get to 100 degrees Celsius at one time. Leave yourself plenty of time to enjoy one of the most beautiful drives around. You do not want to push it on hwy 93, IMHO.
Oh, and make sure to stop at Saskatchewan River crossing for the most expensive expensive gas you may ever find! You probably dont want to risk going all the way from Lake Louise to Jasper on a single tank while towing, and they know it too.
Thankfully, they'll top off your tank for somewhere north of $1.75/ liter, and do it with a smile.
Canonman, those are some great pics!