From the sounds of it you have good access to rock for a lot of the year. So that sets you up well to be prepared for the RGE. If you want to break this down into specific periods, there are two factors that you can use to guide you: your climbing volume (how many pitches you climb), and the intensity of the climbing you are doing (basically the grades you are climbing at). Whatever period you are in, you want to have the intention of increasing your movement vocabulary.
For a ‘base period’ you will want to amass a considerable amount of volume over the weeks and months. Work up to ~20 pitches/week, and go past this if you can. Also, over this time you will want to do a high variety of climbing — not the same routes over-and-over. During this period take note of routes that feel harder or easier and identify why. Take note that it’s not necessarily grades of climbs, but what they demand. You can do this for 8-12 weeks.
For a specific period, focus on two things. 1) climbing that is as similar as possible to the demands of the RGE. 2) the routes that you took note of in the previous 8-12 weeks that were personally challenging for one reason or another. You can also focus on this for 8-12 weeks.
Also, at least a couple of days a week, get out and do a long aerobic effort. This could be a long climbing approach or a big multi-pitch day, a long hike in the mountains with added weight (20-50#), or a long jog/run. Vary the amount of weight you are carrying, and don’t run long distances with a lot of weight on your back.
Hope this helps.