Generator:
"Easy," as you just go buy one (presuming you don't count whatever you had to do to earn the money to pay for it), but since it is gasoline or propane powered you need to carry it outside the rig, plus have a way to carry fuel safely. Also I cringe as I think of yet one more generator in a public park, rumbling away. Yes, the Hondas are quiet compared to a construction generator, but I still hate to listen to them when I'm camping in the woods. They are not silence, birds, and wind in the trees. My personal opinion is that if one is in a campground without hookups, then the proper etiquette is to get by without power, or find a way to generate it that doesn't bother others.
A month or so ago, I was in a primitive campground in the Sierras, and the people in the next site had a "quiet" Honda generator running. At least if they were using it for medical equipment or something I could have understood. But no, they were inside watching football. "Oh, is it bothering you?" Ha, no, I love heading out to the woods to listen to your gasoline powered engine on the picnic table 10' away. Keeps that pesky peace and quiet at bay
Solar:
I can't speak to portable solar setups, as I've only "done" the full blown install type. There will be some system creep no doubt as there are then other things to think about such as controller, batteries, monitor, etc. Maybe less so with a smaller portable setup.
Both the panels and the generator are things that you'll need to think about potentially being stolen. That would maybe dampen my enthusiasm for certain locations/hikes/etc. Location dependent of course.
Cooler:
For myself, for a 10-day trip (that isn't going to be repeated every month), I'd buy a good cooler. In fact I did buy a 6-day Ultimate Extreme cooler this summer and I am VERY impressed with the amount of time it keeps ice. Six actual days and that's not at 40º ambient, either. So much so that I re-considered my plan to install solar/12-volt refrigerator. But that's for a rig I'm using constantly. For a relatively infrequent 10-day trip I would almost certainly choose the cooler. Simple, cheap, nothing to break, nothing to maintain before and after trips (well, wipe it out and prop open the lid). No "system creep." No theft potential to speak of. You can leave home with huge, home-made ice blocks, and then only buy ice once while out. And enjoy the silence
I guess you can tell what I would choose
Viva