Will I have enough points to unlock all skills and enough material to unlock all weapon upgrades?

Yes, it is possible to unlock all skills and upgrade all weapons. I have played ~40 hours, have achieved 100% completion, and have all skills unlocked. I haven't grinded enough after completing the campaign to get enough salvage to upgrade all of my weapons (this is the only resource I'm consistently running low on). I have upgraded all of my bows and pistols, but the upgrades for the rifles and shotguns cost a lot of salvage.

But if you keep fast traveling between the Soviet Installation and

The Lost City

after completing the campaign, you should be able to gather enough salvage to upgrade all of your weapons.