Make the Best of What You've Got
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The fact is that you're going to need nearly a full four days to get from Rhode Island to Breckenridge even by the most direct Interstate route. So unless you can positively add that fifth day you won't have a loft of time to go wandering off. One way to use that four days to readjust to normal life is to mix up the roads you use, switching between the Interstates (to keep the total drive time reasonable) and the US and state highway systems (to experience a little bit of rural and small town America). With that in mind, what I might suggest is that you start out by taking US-6 to Hartford, I-84 to Scranton, and US-6 across northern Pennsylvania. Look at PA-66 as a way to drop down from Kane through the Allegheny National Forest to I-80 near Clarion PA. Switch from I-80 to I-76 just west of Youngstown to avoid Cleveland, the Turnpike tolls, and eventually Chicago. Pick up I-71 south to US-30 across the rural heartland of Ohio to Fort Wayne IN and there hop on US-24 to Chenoa IL where it's back to the Interstates, I-55 south and I-74 west to Galesburg. Next up, some more 'surface roads', US-34 west to Omaha and either I-80 or US-30 up the Platte River to near Julesburg CO. Along this stretch, you will be following the old Oregon Trail with lots of historic landmarks, towns and even the occasional cavalry fort. You'd then finish up with a final push on I-76 to Denver and I-70 into the Breckenridge area.
There are, of course, other similar mix'n'match routes. And taking some of those 'back' roads will add a few hours to your drive. But you can still make that drive in four days. If you have the fifth day you can devote 3-4 hours each day to restful or intriguing stops, enjoying a sunrise/sunset or two, and poking into the odd town that strikes your fancy.
AZBuck