Extra carrybag

The weight of your pack is carried on your hips. A weighted hand-carry sounds awkward & hard work on a multi-nighter. Can't say I can recall tramping with anybody with hand luggage. That's not to say it can't be done, but ....

It's hard work. Anything in your hand gets a lot heavier with time.. that's why experienced tampers avoid doing it.

Not ideal but you may be able to strap the duffel bag on top of the pack. If you can get it stable and it only holds light gear that doesnt mind getting wet it will be far better than carrying it. Long term google hiking and tramping gear lists and compare to what you have. Think carefully about the gear you have and compare to the lists. Your most likely culprit is your sleeping bag. Many cheaper sleeping bags are heavy for the rating but bulk is the big enemy and going to a store that sells tramping gear should find a compression sack that will squash your bag to 2/3 its size. Look at the bags they sell as well. Bags suitable for summer in the Kaimais are not that expensive

Taking from geeves lead; Some packs, like Osprey, have a 'floating lid'. The Osprey lid can be detached and used as a stand-alone daypack. There's room to interspace. https://assets.sectionhiker.com/wp-content/uploads/thumbskeep/2015/03/Top-lid-and-side-compression-strap-attachments.-Osprey-Packs-Kestrel-58-Backpack.jpg Your pack may have strapping on the outside for carrying things externally (as above). You might be able to strap underneath, tho you don't want it interferring with your leg movement and it's likely to get a grinding every time you bottom-out clambering or sliding over something. https://assets.sectionhiker.com/wp-content/uploads/thumbskeep/2015/03/Rear-loading-straps-make-a-convenient-place-to-carry-a-wet-tent.-Paradox-Packs-3900..jpg Either option is going to effect the dynamics of carrying your pack. People do carry stuff in, but the 'right' gear in the right sized pack is gonna work out best.

What pack is it, newguy? and how many days are you planning? I would think a modest pack sufficient for a 3-4 day trip, provided the gear is appropriate (eg sleeping bag as geeves said). BTW, some comments on the two photos and attaching gear outside the pack : 1st pic might be OK in open terrain as shown but, in the bush, those mats will be ripped to shreds, dropping bits of foam all over the countryside. 2nd pic has the mat in a bag - good! but best is in a bag and vertical down tne middle of the pack. Anything packed on the outside also should be clipped on (so, if it comes loose, it will still be attached, dangling).

Thanks for the advice, I will put it to use, & work on my organization. The pack is osprey exos, the top is removable but no daypack straps. I read that option wasnt incorporated into the version sold outside the U.S A 3 night trip was my estimate.

Okay, so it still has the floating lid. So you COULD max it out and slip something laying horizontal in there ?. They also talk about sleeping mat straps ?. That's another opportunity for external carry. https://outdoorgearlab-mvnab3pwrvp3t0.stackpathdns.com/photos/14/28/264359_14247_L.jpg https://www.outdoorgearlab.com/reviews/camping-and-hiking/backpacks-backpacking/osprey-exos-58 As bernieq intimated, excess poking out horizontally is likely to take hits, and unprotected gear will easily get damaged. They talk of the Exos being for Ultra-light packers. It's stream-lined for that. If you don't have the gear for that, then it's a bit like hitching a wagon to a race horse. Over-load.

if you bought it new, take it back and say "It's not fit for purpose, it's not big enough" get a refund and get something bigger... you need a pack to fit the gear you have.. modern packs are designed for modern compact gear, for it to fit in...

The pack's specified load range is 10-18 kg. A 3 day trip for me would be 15kg, not including water. Although the pack is clearly designed for short trips, it should be OK for your plan - all depends on your gear. Usually, the bulky items are sleeping bag (& mat, maybe) and tent. Is most of your food dehydrated? Compact cooking gear? Appropriate clothing without being excessive? So, what's your gear list? and what does it weigh? (the gear, not the list :).