A new character at the beginning of FoV would be level 35, so you shouldn't have any problem being level 34. With D2:ED a few people finished in the low thirties (and a couple in the high twenties), though with difficulty, as the combat in D2:ED was more strongly level based. I don't know if anyone continued with those same characters in FoV, though (assuming they were playing the PC version of D2:ED and had that option).
Which ring are you talking about? If you mean the one two women find on the beach, then that shouldn't have any effect on the grave robber quest. Laura is near a camp high above the beach, across from the grand knight teleporter shrine.
Other than the experience for completing the quest, there is not much in the Lost Tomb, aside from a treasure chest with random loot and a couple malachite veins.
