Shai
There are a lot of ways to gain RPs:
1. Farming RC/RP at Traseia
For me this is the best way to have RPs. It is also the fastest and the surest way in my opinion.
2. Doing Mazey Quests.
Doing Mazey Quests gives you both RPs and MQCs. 1000 Pcs or MQC can be sold at 7 RP - 8 RP if I'm not mistaken.
3. Dungeons / Bosses.
Running dungeons and selling the loots at Market. This really takes time.
4. Merchanting
This is probably one of my favorite. Buy cheap item and sell it to gain profit. This is really risky and you have to have the knowledge about prices and patience in order to succeed.
5. Collecting Area
The lazy way of getting RPs. I mean just set-up tons of collectors and leave it for a day. I know some players who make 10 collectors and sell the items they get from it.
If I were to suggest a way, it is farming RC/RP at Traseia. To spice it up, try a little of boss hunting too. Cos farming can easily get you bored--well at least for me.