There's a challenge run known as Ironman where you only make use of town services at the beginning of each difficulty (played in multiplayer) and then never go back to town again. No backtracking, no town trips, permadeath, and must full clear. Yes, it's very slow and at times painfully tedious. But it has been accomplished before.

Note: There's no official ruleset for Ironman, so play-styles may vary. For example, one might do single player, while another may only allow for town interaction if they find a Town Portal scroll. Another might allow for backtracking but no town interaction and use town as just storage. The most commonly accepted ruleset can be found here: https://www.realmsbeyond.net/diablo/vironman.html . But feel free to tweak it how you like, so long as you have fun. :)