I like this one:
LiFePO4 Prismatic Battery: 12.8V 20Ah (256Wh, 10C rate) (24.0) - UN38.3 Passed (DGR)
Keep in mind it isn't to be charged when below freezing, so hopefully locating it inside the cabin will prevent that situation.
Radio shouldn't matter much, but you should replace your lights with LED. Don't bother with the blinkers though.
If you buy from batteryspace, there are usually 10% off codes that should at least cover shipping.
Keep in mind this battery likely has half the capacity of your pb battery when it was new. It can handle deeper discharging on a regular basis, but doesn't like very deep discharging.