Just hit mid 30's here, played through the mysteries and working though rose missions just now. Difficulty has ramped up a fair bit, nothing I cant handle, but I do have to be a little bit more mindful and tactical as getting amongst it can be a bit sketchy.
I was really struggling for a bit resource wise, trying to complete the miner miracle mission, but since getting to grips with the resource system where and what to collect etc I've been swimming in junk.
Loving my combat shotty, put a lot of time and resources into modding it, its brutal up close, proper ghoul shredding machine! Even makes quick work of a wendigo, forever repairing the damn thing.
I'm running with Gunsmith level 5 on at all times for that reason - it halves the rate at which guns decay. It also increases the maximum condition of guns you craft yourself. Since doing that, I'm finding my guns a lot more practical. I'll pick up weapon artisan perk at some point, so I can swap it in which I repair my guns and thus greatly increase their condition. Without perks, guns in FO76 are made of tissue paper and blu-tac. With perks, they're made of cardboard and duct tape
I'd like to be able to craft my own combat shotgun to take full advantage of the gunsmith perk, but despite scrapping dozens of them I still haven't learned the plan for one. Lots of mods for them and I was lucky enough to find a L40 combat shotgun to mod, but a L40 combat shotgun I crafted from scratch would have a higher condition.
Bulking scrap is useful to a small extent, but with the small stash limit every bit helps. For example, when testing bulking I bulked 180 wood and that reduced my total weight by 3. It's a genuine reduction, not just a shifting between stash and inventory. I checked the combined weight of stash and inventory before and after - the combined total reduced by 3. Although labelled "weight", it's actually a combination of weight and volume so packing scrap together in bulk packages reduces it slightly. It has no effect on crafting - you will automatically take scrap from bulk packages as required, so you're not losing any resources. It also makes it possible to sell scrap to vendors - they won't buy scrap singly, but they will buy bulk scrap. The only downside to scrapping is that it uses plastic, but that's a fairly common resource. Like me, you'll be using plastic to craft shotgun shells but lead will be the bottleneck for that. You could easily have some spare plastic to use in bulking. The weight reduction can't be the plastic - I only used 12 plastic to bulk that 180 wood and 12 plastic doesn't weigh anything close to 3lbs.
Incidentally, you might find it worthwhile to take at least rank 1 of the ammosmith perk, swap it in when you craft ammo and swap it back out afterwards. Even rank 1 gives you 40% extra ammo from crafting while using the same amount of materials and I think that's useful considering that lead is quite a bottleneck on ammo crafting.
I came across my first set of PA about the same level, but it pretty much just took up space in my stash until level 25, when i could start using the T45 set i had found, but if you are brave enough to go hunting for it Raider PA set can be used much earlier ~Lvl15?
Yes, L15. But it's marginal IMO because unless you're server hopping by the time you find a full set of raider power armour you'll probably be L25 anyway and could use the much better T45.
I'm currently rocking the set I built for the Miner miracle mission, but close to completing the T51b set. I have an almost complete T60 set(missing one of the legs) but its levelled way above what I am, so wouldn't be able to use it at the moment anyway.
I'm in L40 T60 but with a L30 T51b torso because I haven't found anything better. Maybe I'll get around to the Miner Miracle question, but the miner armour is worse than T60 anyway. Good rad resist and a big bonus to carry weight, but less ballistic and energy resists. Although the quest might also give the power armour station crafting plan as a reward and that would be useful.
By the way, you can craft improved miner power armours at higher levels since you've learned the plan for crafting it. I think L35 is the next step up. Might be useful to you.
For me to get the key to access that vault was really obscure & time consuming I saved you many hours!! 
At least you got that rare PA paintjob & few Nuka Cola clothes now. 
got some mad XP though!
(you need to fix about 15 but destroy about 32!!) this is once again whilst under an extreme assault from all the robots & ceiling turrets. Then & only then can you open the final door. That is why its such a PITA.