Greetings Iazin!
Moon Guard is a good server to pick for returning players as it is a full server and the large number of roleplayers give it a really lived in vibe.
I will be honest, in order to fully appreciate the server long term it would probably be better to find a roleplaying guild, be it light, average, or heavy. If you think this may be a six month stay, then a dungeon/social non rp guild would probably be the best bet to see dungeon and LFR raid content quickly.
I will say the Kul Tiras Marines is a good guild for those that are just starting out on the path of discovering roleplay but have a focus on the game. I’d classify us as an average roleplaying guild instead of light or heavy. We’re the oldest Kul Tiras guild in the game and have been playing since launch day as well so we have several experienced players. We only have two content devoted nights with a normal difficulty raid on Mondays with our allies and rated battlegrounds on Fridays. Any time between is spent playing the game either doing dungeons, Torghast, or random battlegrounds.
We don’t normally do the campaign style d20 campaigns unless one of our more heavy roleplaying aligned allies invites us. Our way of introducing players to the world of roleplay is Boot Camp. Over a couple of months, your character, in a roleplay sense, will be treated as a cadet and have to attend classes where we explain the lore of the guild, the lore of Kul Tiras, and teach you tactics you can use as your character (giving you tips on your class). We usually hold one class a week and switch up the days and times so that people that can’t make a certain day/time can make it other days/times. It’s not a rush to get a new recruit through it since we want people to enjoy the game and not worry they are spending all their free time having to attend rp events. Once that character finishes Boot Camp, they will become a Marine. Any rp events beyond that focus on the story of the game.
Out of character, when a recruit joins they are treated as a member. The recruit designation is just an in character element. Most of our guild is late 20s to late 30s with some younger and older members. From your interests, I can tell you that we have some very similar minded members. I’m not going to advertise what they do cause we don’t want people joining for the wrong reasons, but I’m sure you’d find some interesting discussions.
Our main recruiting thread is below:
https://us.forums.blizzard.com/en/wow/t/a-rp-pvp-kul-tiras-marines/785778