Hrmm... some thoughts on : Smaller bike vs a full-on BigBore bike in this application.
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Well... the seat height is one. The more and more tricky and technical a lil single track goat trail becomes, the "bigger" your bike starts feeling.
If a person has substantially less experience, a BigBore bike can get 'em into trouble in the blink of an eye! The InterWebz is absolutely chocked-full of endless whiskey-throttle crash videos, HA!
But... at the same time... if the user has setup and dialed-in their BigBore machine to be more oriented towards trail/enduro then they can actually be easier to ride over sketchy terrain. Since they have more power on tap, and since folks tend to slap on a slightly heavier flywheel, to tame down the hit of power, while simultaneously improving it's climbing and slow-going tractability.
Biggest thing I'd say is... really determine for yourself if you believe you'll be Ok, in the kinda places you ride into and thru, with dealing with long-legged taller seat-height... when ya got a heavy pack on. REPEAT: When ya got a heavy pack on!
Also most of today's modern bigbore bikes for Track or Dez.. have very thin padding on the saddles. A lot of trail-oriented or dual-sport models tend to have slightly nicer more cushy seats too (but NOT ALWAYS).
For tight technical goat-trail type stuff on a BigBore bike... like all of a sudden the trail makes a hard turn and "Oh Shoot!" starts climbing up steeply, with no run at it, and it's chocked full of human-head or bigger sized stones... on a BigBore machine... if you understand how to click into a higher gear than you think you need, and slightly feather the clutch while you're executing the climbing over those stones... it makes the rear suspension better eat-up the bumps, rather than you being all wound-out in 2nd and bouncy-bouncing all pogo-style up the same climb. The latter taxes you much-more energy-wise throughout the day. So always remember "Clutch is Key!"
For mountain trails, I'd definitely recommend making sure the front brake actuation is a nice and light 1-finger dealio. Hydraulic clutch/brake levers are AWESOME for feel. But...they do introduce more potential points of failure though. So if you elect to go with a model that's cable-actuated.... also think about getting teflon-coated cables (Terry Cable, or whatever other manufacturer makes them these days) if your application involves cable-actuated. That also saves you quite a bit of forearm pump. The more powerful bigbore bike will require stronger clutch basket springs, so these little things to ease that clutch pull for you pay dividends over the course of the whole ride at staving off forearm pump.
A front brake that has a good and precise feel (modulation) to the braking in the lever. Cause when you have to ride the brakes down a loooong downhill single-track goat trail... you wanna do all you can to lower your amount of forearm-pump you'll experience, because when you're going down that slow technical trail.. your pack and it's weight are gonna make your triceps BURN! HaHA! So reducing fatigue from forearm pump will help ya not have to stop as much along the way down to let the pump calm back down.
REMEMBER: Thee biggest thing that causes crashes offroad is fatigue! fatigue! fatigue! And in a hunting application you're doing a lot of out of the norm things. That heavy pack and rifle being strapped to you would change things a lot. It makes the need to be able to ride comfortable SEATED become much more important. Again, referring to the skimpy saddle cushioning thing. If you pick a model that does have modern thin seat, I'd definitely look into getting a Gel Seat, without question.
Another thing to think about that might help make your decision is to consider the terrain you'll be riding in and decide if for you... that terrain is rough enough that it'd be a good idea to get highest ground clearance you can manage to ride well or not. Like... if I knew the trail going in might have lots of fallen logs crossings that you can't avoid going around... that'd influence me to lean more towards a taller, more serious type of offroad ride. As oppose to the more svelte and easier to sit on and ride lower, less powerful bikes.
Also there's things to consider like your body weight and level of aggressivenes while riding... considered in the context of the lesser trail bikes, because sometimes, for example, they might have fork tubes that are lesser in diameter and potentially could be prone to fork flex when pushed with too much weight, especially with a 200+ Lbs rider on top.
Before anything though... very first thing you should be doing is setting up suspension sag for your weight (with all your hunting gear on, minus pack). It is a NIGHT and DAY difference the handling you'll get from the same machine... when you try to ride it without dailing-in the suspension for your weight/aggressiveness. It'll handle _HORRIBLY_ if you don't take the time to set up sag and spend some time riding over things like some whoops and checking out how she handles decelerating over braking bumps. And learn how to adjust your clickers both front and back, to further dial-in the ride for you, specifically! Motos are much like guns in that respect, you need to dial them in for you specifically!
If you're in the 200+Lbs club... with a Trail bike or DualSport, chances are higher than you'd think that you should opt for a stiffer aftermarket spring in the rear. Sometimes you can "Meh" kinda sorta get sag set "decent" by tightening up the preload adjuster on your rear shock. BUT... this comes with the cost of making that rear suspension less supple and more "pogo-y" in the rear.. over smaller bumps. An example would be like braking bumps in front of a corner. The rear-end might get a little more "busy" waggling it's tail a lil side-to-side as it gets unloaded during the braking. So something to beware of.
If you get a bike with a keyed ignition (such as on dualsports), definitely make sure you have a schematic of the ignition switch. So that way if you crash out there and the ignition switch takes a hit to it... you can at least find the wires, strip 'em and make the connections to be able to start it back up and get back home!