You could do a two day on the Cache La Poudre, day one run Upper/lower Rustic (III-IV), camp somewhere in the canyon, then do Stevens gulch (upper mishawaka, lower mishawaka, poudre park, bridges) down to bridges takeout (III-IV(+)). But it isn't a continuous section, there is a class V+ section between day one and two. You'd be car camping not taking your gear down river with you. In fact there are few true multiday runs in CO, mostly car camping in close proximity to sections you could run on back to back days.
Otherwise considering your preferred proximity to Denver the aforementioned Arkansas and upper Colorado are the only real options. The Ark will be near peak flows and a ton of whitewater fun. The Colorado is much more mellow but will probably be a bit less crowded.