Map complete - need advice
The colour of your team is based on your position on the ladder. Green is highest in the bracket, blue 2nd, red bottom. So if you’re in a more mid-tier server such as mine (Maguuma), your colour will change from week to week, therefore allowing you an easier time to get points that may have been deep enemy territory in earlier matches. However there are some exceptions that I can see, Kaineng for example is at such a severe WvW disadvantage that for the foreseeable future they will always be red.
Based on this you should be able to decide if you’ll need to do some server hopping or not.
I would highly doubt ArenaNet will close free server transfers without at least a couple days of warning. Just check which servers are where you need to go so you can make the most effective hop possible.
If you’re really worried though, you could save up the gems for a server transfer first (maybe even ask your friends to help you with that), so you have a safety net if you ever get stuck.
Thanks for the answers. That does help understand how it works a bit better and in turn, helps me make my choice.