You're trying to ride two horses with one saddle IMO.
If you're planning on hand carrying a rifle in the woods and think it's practical to actually take an off-hand shot with it, get something short, I mean like a 16" barrel. Whatever velocity is lost is made up for by the shot being close enough that you probably are struggling to line up a 2x power scope and the yardage is most likely only in double-digits. I built a 338 Federal just for this exact use - big heavy bullet and slow doesn't matter because it's so close it still smacks hard. Instead of paying to re-barrel a rifle not built for this use, I'd save up and get a complete second rifle. There are a lot of good factory choices around the $1,000 level that will come with threaded 18-20" barrels.
I also shoot a 30" CF barrel with a 12" TBAC 338 Ultra. But it's not like I carry it around with the can on it all the time - offhand shots are oh so very rare when carrying a 14# 54" long rifle in a pack
Takes all of 5 seconds to screw the can on when it's time to dig in with the bipod and set up. I use a TBAC brake permanently mounted on the rifle, and the can is very repeatable coming off and going on.
TBAC Ultra 7 has been my go-to for several years now. But I just got an AB Raptor that might take the top spot over.