Truk in TMO25 without RSRD is ridiculously easy, with half Japanese fleet "parked" there. OK, maybe not half, but 2 BBs, a career and couple of heavy cruisers, destroyers and quite a lot merchants - easy pray, no defenses. Just go at night - a lot of aircraft during day time. And dont do it every patrol, gets boring quickly
Or dont do it at all - there is possibility you will loose some respect you have for the game