Supercharged 4-cyl fuel-grade and mpg?

Have any of you compared your before/after mpg with a 2.7 supercharger add? Do you have to run premium for that? I wouldn't think so, but it was said here somewhere.
Here's the story, if interested.

Demelza (2.7, 4wd, stick) wasn't bought for towing, so 4 cylinders have been plenty, but then Covid said we should get a camper.

Normal ~20mpg drops to about 15 towing, which is fine - i get it, but it's kind of a pain hopping from 4th to 3rd to 4th all day, so I'm weighing the options after sifting through a dozen threads on the matter. I'd rather boost power than re-gear or reduce tire size for non-towing speed and fun, and the most common suggestions here, more or less in order of power, seem to be:
1. Buy a V8 (whatever)
2. Drop-in a V6
3. Supercharge the I4
4. Internals (higher cam, stroke, etc.)
5. Exhaust and bolt-ons (CAI, throttle-body spacer, etc.)
6. "Free" stuff (deckplate, shave weight, etc.)

I think i need more than the 5-10hp boost the deckplate would allegedly give, so i'm pretty much looking at options 2-5, obviously wondering what's just enough for small-camper towing, best bang-for-buck, and least time invested to get it (i do my own work, if/when qualified, so time's a thing). But what no one ever talks about in power discussions is mpg. Thoughts...?