Hi and welcome to the forum!
I didn't have a full drumkit for quite some time either. But what I did was getting a double pedal & kick practice pad (and a few practice pads for handwork of course) to start practicing the motions - because they're the same. The sound will be different of course but lower practice volume is a good thing. Admittedly, the playing/feel is a bit different, too, but overall practicing with pads (feet/work) is worth doing it.
Here's my double pedal practice rig - affordable (if not cheap) dw2002 double pedal, HQ RealFeel kick practice pad (with additional foam/rubber on top, plus a blanket for less pastic, more pleasing sound. This is to inspire you to find ways to practice wherever you can and as often as you can - I have this rig under my PC desk and (working at home) this way I can practice for hours (while doing other stuff with my hands). Think multi-tasking.
http://www.youtube.com/watch?v=PnGNok9SHsM
Here's a thread I made with more details/pictures to give you an idea of how it's working or to inspire you to make something similar. You can even make your own kick practice pad from scratch if you want to, for close to zero money.
Double pedal (dw2002) & HQ kick practice pad mod
http://www.drummerworld.com/forums/showthread.php?t=97507
To improve with double bass you have to put in the time/practice. So find ways to practice as much as you can.
Use the
search function (e.g. searching for the terms "double bass") and you'll find a lot of info on double bass on this forum as this topic is coming up regularly.
As for RLRL - basically yes. This refers to starting patterns with your R foot but depending on the pattern, maybe some notes are left out so you would start with your L foot at times. So RLRL would be the 'correct' way for e.g. 8th, 16th notes etc. (although some stuff can be played with one foot if it's not too fast - both feet can be used, too but that would be the 'lazy mode'). As a starter I'd recommend playing 'endless' note sequences - 8th/16th notes. Switch between one foot (R foot for a while, then L foot for a while) and both feet at a time. Also try to play with your L foot leading, this will help you strengthening your L foot (and L foot awareness) because your weaker foot is the foot that keeps your speed down.
Are you motivated? Do you have time, patience and discipline? GREAT. Get started ;-) And don't get discouraged if progress won't come overnight, because it won't. That's normal. (Plus, don't forget there's more important things in life than double bass, haha.)
Now if you don't have a (double) pedal at hand you can even practice without one. That's not as effective as practicing on a pedal but still better than nothing.
Once you have a good flow of 8th/16th notes it's time to move on and focus on patterns/shorter note groupings like 2, 3, 4, 5, 6 notes. You can also practice rudiments (or e.g. stuff from "Stick Control") with your feet, that's a great way to develop more control.