You can start with 30 Ranged Combat and make it work, my current character as well as several previous did. If you hire two top-tier mercs they can carry you a while. There's a damage bonus to higher RC, but weapon type determines damage more.
It becomes economically viable when it saves you from firing coil or plasma guns at enemies with 10 hp left and/or little armor, and when you want to capture opponents for a significant cash bonus. The more you do it, the better you'll get at it. I'd recommend training Strength first, then Dex. Don't bother with Melee Combat as you'll crit yourself to the cap anyway. Train Rebecca or a captured 'lonely bandit girl' with you and you'll have two good Melee combatants in short order.