I really suggest just getting the trial first and then doing the raptr.com thing. You only need 3 hours of played time - and believe it or not, you'll only be around level 10 by that much time played realistically. Totally worth it, you get a free game key and 30 days of free play time. Worked for me two days ago, just got the full version.
Only problem is that with Rift, you need to manually track your hours - but its as simple as going to the Rift page on Raptr and clicking "Manually track playtime" or w/e on the left of the screen and enter how much time you intend on playing. 3 hours later, free game. Such a good deal.
Are Dimensions available to Rift Lite players? I started a Mage, but when I received the quest "Placing Dimension Items" and attempt to teleport to Warden's Point, it looks like it tries to load me into that place, but I end up eventually getting sent to Meridian.
Yeah the smallest one is... Lvl 7 req. Talk to the dimension engineer in Meridian.