What 'Son of Norway' said twice...
Highway 34 through RMNP is the sort of Road that needs the Signage: 'Vehicles Over 35' to Kingpin Are Not Advised'. The turns around Rock cuts can be tight, so I recommend disconnecting the Toad. Touristas do some really goofy things, like stop partway in the Road to 'get that picture'. There's Turnouts where Road Engineers could put them.
At the stunning Alpine Vistor's Center at the Summit, you're just shy of 12,000' elevation. Air is ~25% less dense there, and this affects Engine Cooling; especially when stopped. On a peak Summer Weekend day, the ample Parking up there can be tough for a Big Rig. This, too, will be easier w/o the Toad connected, as will be the parking at various Turnouts. However, Big Rigs are expected, and parking is 'friendly'.
Late every Spring, the Road Crews attach these 'Rotomills' on the front of huge Tractors, and have to Snowplow through 12' Snow Drifts. It's a big deal every year IF Trail Ridge Road (Hwy 34) opens by Memorial Day. Sometimes, it doesn't. So, check the Links below first. Late Snowstorms and a late thaw this year = more Snow up there than 'usual'.
When I've hauled Int'l Biz Visitors up to RMNP, I very occasionally have been stuck behind a big RV that died. But, it's rare. About every Turnout has stunning views, so pull over and enjoy while the Rig cools IF that's an issue. It clouds up here about every Summer afternoon and cools down; especially at those elevations.
On Google Earth, you can invoke 'Street View' and 'drive' Hwy 34 as seen by the Google Car that drove that route and stored all the Video of it. You can also invoke 'Panaramio' on the Google Earth Webpage left side and see lots of Pictures that Visitors have uploaded. Last, by putting the Cursor on the Road while still in Satellite View from above, you can read out Road elevations and get a sense of Road Grade and see tight curves in advance for yourself.
There's lot of Big Rigs up there in the Summer, so no need to be spooked by that Route. It's a stunner... The RMNP Staff linked below will have helpful advice.
Rocky Mountain National Park InfoColorado Road Conditions