Welcome back!
For easing back into the game, I would start a brand-new character and level from scratch if I were you. I think it will help familiarize you with how a given class works now and how you’ll be routed through the world in a way that boosting or picking up an existant character in the middle of the leveling process won’t.
Personally, I still much prefer the racial starting zones. However, Exile’s Reach provides a more gameified tutorial mode. You’ll be able to choose between Exile’s Reach and your racial starting zone when you make a new character (if you haven’t seen that already).
For RP, if you’re asking about Wyrmrest Accord specifically, there are a couple of hubs for random walk-up, but most RP on WrA is not random walk-up.
For random walk-up, your best bets are the Valley of Honor for Horde and Duskwood (including but not at all limited to Darkshire) for both Alliance and cross-faction RP. Reviews of Duskwood are overwhelmingly positive, but reviews of the Valley of Honor are mixed; VoH tends to have a fairly big crowd, especially in the evenings, but it sounds like it can be plagued by OOC players using toys and chatting in /say.
However, you are not limited to walk-up. In addition to guild RP – if you’re inclined towards joining a guild – WrA features a large number of both one-off and recurring RP events that are open to general participation rather than being guild-locked. Some are Horde, some are Alliance, and many are cross-faction. If you’re not looking for a guild but are interested in campaign-style RP, there are also sometimes open campaigns, currently including Year 40: Dragonscale and Helping Hands.
You can find a lot of events by scrolling recent threads here on the realm forum, and you can also find them on the calendar of the Wyrmrest Community Project Discord server. The WCP is a great place to be for finding RP in general, having a lot of people to network with and a channel for seeking semi-organized RP in. For that matter, a lot of gameplay questions can probably be answered in the gameplay and general channels, as well.
Hope to see you around!