In DKS I maxed Ranger Strength, Ranger Stealth, and when available boosted Explosive Arrows and Splitting Arrows as my main special attacks. Mana Efficiency helps with the mana requirements of bow skills, as does Increased Mana enchantments on armour (though I always went with Life Line first), and allowed me to avoid putting any stat points into Spirit or Intelligence (though you would be boosting them if you wanted to do a mage hybrid or switch to a mage).
Early in the game Poison Arrows and Stun Arrows are quite helpful, though after getting to the battle tower and re-learning skills, I only put 1 skill point back into them (mostly just to use them as a way to pause the game, select a target, and come out attacking, since a normal ranged attack does not unpause the game).
I put 1 point into Death Blow, Evade, Healing and Regenerate.
Late in the game (in the FoV section) I tried Way of the Ranger (after getting it as an equipment bonus) and immediately put 5 skill points in myself, later maxing it. I'm not usually a fan of temporary boost spells/potions/etc but WotR makes a significant difference, especially combined with Splitting Arrows.
If you talk to your trainer to work on your skills, the option to unlearn skills is at the top of the list showing available level cap upgrades. The price to unlearn skills doubles each time you do so (though you should have enough gold to reskill at least a couple times, if you are so inclined).
There were some changes made in DKS to ranger skills (Explosive Arrow damage was cut in half) and I never tried a ranger in the original D2:ED, but you shouldn't have any trouble finishing on difficult.
