With no status and if miles don't matter, I'd probably take FL and buy the upgrades ($40 or $50 each way). If you can snag an exit seat on the B737 then maybe only upgrade on the B717 coming back.
If you're looking for interesting planes, I'm afraid you're out of luck with all mentioned. The MD80 is a workhorse but about as dull as it gets. B717 is the same (DC9) airframe with different engines/avionics/ect. The B737 is the most ubiquitous plane in the air and the CR7 is just misery with slightly more people on board than a -100 or -200.