Personally i think even in stock form the 300 is a better performer then the 302 for streetlight to streetlight runs, or anything to do with towing.
The 302 has more horsepower, but torque wise they are close (265 for a later 300, and 275 for a truck 94+302), difference is the 300 probably has twice the torque off idle the 302 does.
In a Ranger big deal. Not like you are going to put a gooseneck on it and haul bulldozers.
I have never driven a pushrod 5.0 F-150, my admittedly mild Ranger build has never left me wanting for power. In low range (for speed more than anything) I pretty much just idled around SOP. Point and click, it was awesome (to me anyway) Stock 1987 shortblock with stock E7 heads and a Mustang cam.
I imagine I have said it before, the M5ODR2 out of a '97-03 (and '04 Heritage) 4.2L F-150 fits the best, the shifter is farther back like a Ranger M5OD. The 4.2, 4.9 and 5.0 and share the bellhousing pattern, I used the flywheel/clutch kit for a '96 F-150. Get the separator plate for the same, not the V6 one. If you are planning big tires and big power you might consider bumping up to a ZF. I have read a lot of fullsize guys complaining about the M5OD not staying together in more built rigs that are ran hard. I have about the same engine (200hp 302) gearing (3.73) and tire (31x10.50-15) as a mid 90's F-150 in a much lighter carcass so as far as trans goes it should have it easier than the trans in a stock 5.0 F-150. Or if it is going to be more of a trailer queen or if you don't care so much about mpg one of the old 4 speeds would probably take the power decently for a lot cheaper than a prized SBF ZF.
For the M5OD you have to make an adapter ring to mate the t-case to the trans, if you need it I have that drawn up in a .dwg I can send and you can have a shop burn that out for you. Extension housing will need some modification too for the RWD shift rail and countershaft nut. Not sure what all is needed with a ZF, I would suspect at least the extension housing would still need modified.
If you want to go nuts with it you can add a doubler to the 205 have a triple stick...