Forget about the concept of running 2,500 RPM cruise. If you want that you need to go to a 1:1 ratio (direct drive) and forget about running ground. To run ground you want to set your max RPM at max Hp, simple as that. Torque peaking a bit lower is perfect, that will give you throttle response, all of which improves ground running. But your cruise RPM will be up there (70-80% of max) since the prop makes minimal thrust at lower revs.
Honestly, given the specs cited, you have a motor built to run a low ratio with motor spinning to 4,500 or so. The gear and prop change proposed will probably improve things a bit (on both fronts actually), but won't get you where you really want to be.
You should seriously consider some motor mods before spending big money on gear and prop, 350's are the cheapest dollar/Hp value on the market by far. You don't cite a pitch setting on your present prop, but I would try taking some pitch out of what you have first and let her eat. 350 motors do their best work between 4000-5000 with easy mods and 5000-6000 RPM (and beyond) without breaking the budget. On a low budget ($1000) I suggest a Vortec head and cam mod. On a bigger budget start at the bottom end and build a lopey roller motor.
Once you have the motor sorted, then you can consider the best prop and gear.