Day trips for me are to waters within two hours of home. I have a few good ones worth the drive, one only 45 minutes. Places 2-5 hours from home are long weekends or at least 3 days. For example, from southern Wyoming to northern Wyoming. Some of my annual haunts that are 6-10 hours from home are usually 10-40 day trips! Its a gamble to go that far for just a few days. Weather, bump in flows, etc. I take a month, twice a year, in ID and MT.
But its interesting, once I get to the "golden triangle" area, the "great" waters are all about 2 1/2 hours from each other, so sometimes there's day trips within the long vacation. I'm on the Fork, it slows or conditions crumble. Boom, a quick hop to the Beav. Or the creeks. I'm on the creeks, or the Beav., and need a change. Boom, 2 1/2 hours to the MO! Not to mention a few unmentionables in between. SW Montana to Silver Creek, easy to do in an evening. Silver to the Boise, or even the O, another short afternoon or evening depending on seasons. Ok, that's some name dropping, but I've done "day trips" from one river to another frequently. Madison to the Fork is under an hour, and I've been known to fish the Fork in the morning, take a nap and lunch, and then drive to fish the Maddy until dark. Return and repeat. Same with upper Fork and lower Fork, or the waters slightly southeast of that within sight of both sides the Tetons. Day trips from the destinations, to more or newer destinations.
But that's how I think of them. From my camp, "where am I going today?" Home based, ya, within two hours.