Oh my, the crafting log? Well that will become expensive as well as time and inventory intensive. Leves beg to be used for crafting jobs. Turning in HQ items to a crafting leve gives absurd amounts of experience (2x normal -- with normal being much higher than for combat leves already).

Leveling BTN before WVR makes things much easier, though you may want to just go ahead and level CRP at the same time. While leveling BTN you can gather far more resources for both WVR and CRP than you will use to level both classes the same amount as you leveled BTN. Gathering for CRP is super simple as well. Just get a few stacks of every log and you're pretty much done.

Most of your exp gains come from leves. Always turn in HQ and use triple turn ins (easy to spot being that they reward you with significantly less exp -- though you get to repeat them 2 more times for the same 1 leve) if you're trying to maximize exp/ leve. I prefer courier leves since they give the most exp per item and travelling is quick and simple until level 40 (where it starts taking some time). Since you can gather your own materials, you can reduce the cost of things a lot. To avoid inventory issues, try to just gather a lot of what you will need and keep track of how much oddball stuff you might use (for instance some later WVR recipes use a single cotton ball). The only things you should need to buy on the MB are crafted items form other classes (various leathers, glues, ingots, etc.) It will be hard to HQ much on your first crafting class because you'll lack cross class skills, however saving HQ materials you gather for times when you absolutely need to HQ something (class quests) will help.