50mg / day kratom...? Do you mean 50g? I assume you must do.
That being the case yeah I'd say you can use klonopin to mediate some of the shitness that you will definitely feel for a while. On balance I'd say that GABAergic addictions are less desirable than kratom but you don't have enough of anything to develop a problem really, so if you really mean that you'll be out when you're out and won't try to get more of whatever, then what I'd do in your situation is take 1mg / klonopin per day for the first ~6 days (actually I'd personally expect to go through it more quickly than this, maybe only in 2 or 3 days, but keeping to 1mg / day is an aspirational target and might well be enough depending on your experience with benzos / other GABA-ergics and your general disposition).
This almost certainly won't deal with all the withdrawal symptoms, you'll probably still be fatigued, and probably will experience all the classic opioid withdrawal symptoms (muscle aches, general run-down-ness, yadda yadda) but it potentially will deal with the bulk of the major psychological impact and allow you to be a little nicer to yourself inside your own mind while you're dealing with the physical stuff.
After that go onto the gabapentin, IMO/IME gabapentin is just not that good compared to basically any pharma benzo or other GABAergic I can think of, and does not really do much to combat the psychological stuff but hopefully the clonazepam will have got you through the worst of that, and the gabapentin will help with sleep and some of the lingering physical stuff (muscle aches mainly I guess, it being a muscle relaxant). I'd probably aim to take 1200-1600mg gabapentin per day, spread out, leaving at least an hour between doses (due to gabapentin's weird absorption). Definitely don't take any more than 400mg at once because it'll be a waste but if you want to take more than 1600 / day total, I'm sure you can, no doubt it is possible to take too much gabapentin but for me it would be a big challenge, not sure why.
So that should make the acute phase of the withdrawals a bit more bearable, I'm pretty sure I've done something almost exactly like this before as I've withdrawn from kratom multiple times, and used klonopin and GABApentin on and off quite a bit, so I'm sure there was some overlap even if I wasn't always organized enough to remember it exactly. Actually most of the time I've probably just cold-turkeyed it, with just gabapentin as for me it is just barely psychoactive and usually during withdrawing I develop a kinda aversion to any drug that is too "heavy", which would rule out klonopin. However if I was planning this rationally rather than just my usual unplanned yoyo-ing between dependences, for sure these 2 substances would be a good choice, I would probably try to start out with a lot more klonopin but from a harm reduction perspective that probably isn't a good plan.
With the amounts you have available though, I really don't see anything wrong with this idea, it seems safe, you don't have enough of either substance to develop a problem with them and they surely will make your experience a little more bearable. Good luck!
