Get a proper backpack, the kind that you can lie flat on the ground and open up, not a top loader, not a little shoulder bag. I carry an RB67 with two backs, three lenses, filters, a spot meter, a tripod and miscellaneous other stuff and it is not that heavy. Once you get used to it, you will love it.
Funny you should say...I forgot... I DO have a good back-pack.
Never really needed it for 35mm...a shoulder bag always sufficed. So yes.....The back-pack will be perfect.
Thank You