The PVC pipe will work, so will those plastic golf tubes you can buy for a $1.

I paddle a SR 16 tandem back wards ( rental canoe) I keep 2 rods rigged. I Bungee Bob a tube under each side of the bow seat. Depending on rod length/ rod guide size, you might have to trim tube length accordingly.

I like 7' rods, so with the top 2' foot or so of the rod in tube, the handle is under my seat and Bungee Bobbed in place, either side of me.
I like the single tubes becasue they keep the rods separated and the guides protected, but the principal is the same no matter what size tube you use. With 2 paddlers, the bow guys tubes are under the stern seat and visa/versa for the stern guy.

On open trails, the rods are well protected, but if your bushwacking. or the trail is overgrown in places or full of dead-falls, you might want to use one of those nylon rod sleeves that will protect 90% of the rod/line from snagging up.

I'd work all this out at home before you hit the water. If it's your own canoe, I'd substitute some good heavy Tie/Wraps on the tube end. I think most people that try this type of set-up, are pleased with it, once they adapt for their gear requirements.

Strong legs and core (abs) are the key. Strong abs will protect your back when lifting. Exhale on the lift, suck in and keep your abs tight until your load is balanced.  Any of the exercises mentioned will do the trick. The tip about loading/unloading packs being as tiring as portaging sometimes is right on. There's nothing wrong with having your partner hoist the pack and you slip into the shoulder straps from a balanced/upright position. Then you do the same for him. Solo, I often set pack on bow plate of canoe/log/rock , then turn and slip into it.

I'd bet that more than a few paddlers have wrenched their backs/hips/shoulders, trying to lift a heavy pack, especially on uneven surfaces or from an awkward position. It makes NO sense to plan a great trip and then hurt yourself the first day out and suffer the rest of the trip. Same advice for portages. Don't let your ego write a check your ( * ) can't cash

It must be just me as everyone else is in agreement........I've not noticed any undue fatigue lifting packs out of the boat or to much problem getting my pack mounted. Maybe I just never paid much attention to it....I dunno.

One tip that I find helpful is to loosen the arm straps, gather the excess strap while you mount up (so it's not prone to work its way under your main padded strap) and then it is a simple matter to pull on the excess strap to tighten everything up. I like a snug ride.

One more vote for the golf club tubes for rod protectors. I’ve just seen too many times when a pack is going in or out of the canoe when a section of the line or the rod tip itself gets snagged. The tube covers the most delicate part of the rod. One positioned in a convenient location for bow and stern positions. Drilled some holes thru the aluminum strip under the gunwale and used cable ties to hold them in place. Take the butt of the rod and hold it in place with a bungee dealy bob or a strip of Velcro for portaging; just rest in on a thwart when traveling from one fishing spot to the next. As far as weight, I’d be surprised if the entire setup weighs a half pound. Not like that nasty heavy PVC.
Certainly a matter of personal preference. This is a system my partner and I agreed upon (also co owners of the canoe). Another member of our tripping party was in attendance while we were doing the install and mildly ranting about how we were wasting our time; nobody needed such a foolish system. I checked; we were doing this on our canoe; not his, so I’m lost as to what the big deal was. Different strokes and all you know.
We did a two person trip. Portage routine was we would land, get the food pack onto his back and he would set off down the trail. I would finish unloading the canoe, load up, and meet him along the trail on his way back. By the time I got to the end, and got all the stuff that was already there back into the canoe, it was not long until he showed up with the balance of the gear. Actually went pretty smooth. Another benefit was the food pack was not left unattended for very long.

Having primarily traveled in larger groups and single portaging for much of my tripping experience, I can honestly say that I understand your concern.  Trips of late have been with fewer people, 4 in 2 canoes and up to 3 in a single canoe.  Often we double portage at the beginning of the trip due to the food pack's weight, then are able to single portage for the last third of the trip.  Since I usually carry a canoe across first, I look at the second trip as a nice walk to see what I missed.

For 11 days, my food weight would be more like 45-50 lbs. for 2.  We don't bring that many fresh foods, but we like to eat well and don't bring much dehydrated stuff.  I would say that Preacher's weight quote of 25 lbs. is ultralight.  A Kondos or CCS food pack sould all of your food easily.  I suggest each person pack in own daypack/overnight style pack with room to put 1/2 of the shared gear.  That should result in an easy second carry.

Other than that, I'd suggest looking at cooking/crew gear that you usually bring and pare it down.  You might find that you don't need a large pot, or that it doesn't make sense to put cooked food from a pot into 2 bowls, etc.  Perhaps a dining fly is a luxury you can do without.