I did this. Start with Oathkeeper, melee S&B with Aegis of Menhir as AoE/nuke ability.
- Your spam attack - Righteous Fervor - goes to 16/16 or 24/16 (if you get the gear with + to RF), its Consecration modifier - to 12/12 and 1/12 Retribution.
- Aegis of Menhir - all points to max level, its Avenging Shield modifier - to 10/12 (to get 4 target bonus) and 12/12 Reprisal.
- Summon Guardian of Empyrion - one point, its Celestial Presence - at least 12/12.
- Divine Mandate - all points to max level.
- Ascension - all points to max level, its Clarity of Purpose modifier - one point.
- Resilience - one point.
- Presence of Virtue - all points to max level, its Haven modifier - one point and Rebuke - all points to max level.
- Vire’s Might - one point, its Tectonic Shift modifier - one point.
- Safeguard - all points to max level.
- Smite and Shattering Smash - 10/10 or 11/10.
Only at ~80 lvl I started investing points into Inquisitor mastery and its generic skills like WoR and Deadly Aim. Almost solo Oathkeeper all the way through vanilla Veteran and part Elite difficulty, it is quite doable. Devotion tree path was mentioned above, only bind Assassin’s Blade to Aegis and Ulzaad to Vire’s Might, since we do not use Rune of Kalastor during leveling process. Use common gear with %Physical Damage, bonuses to RF and Aegis, resistances to not get one-shot. Avoid Physical-to-Something conversion on weapons, shields, amulets etc. Then respec/equp gear at lvl 94. Done!
It is only viable if you have all endgame gear waiting in your stash. If not - use one of Beginner’s Guides to make somewhat usable Oathkeeper-based class to farm totems/dungeons/low SR and so on. And then respec when all gear is collected. Depends on what you have.
Sorry, I am not good at beginner’s guides 
. I hope that at least some of those directions will lead to success. Good luck!