It shouldn't take you more than 18 months tops if you have taken your basic college courses. If you haven't, then I'd say 2.5 to 3 years.
I'm an LPN. I have 146 hours of college credit. If I wanted to get my RN locally i would simply take a summer bridge class, and then two semesters of nursing and that would be it. You can go from lpn to rn or lpn to bsn online as well. It is pretty convenient but it's not exactly the cheapest route. You have to do the clinicals of course, as those can't possibly be done online, but other than that almost all of your course work would be done via the net.
I'd say if you haven't taken a college course getting your basics could be done in a year if you wanted to and then you could bridge over the next summer and then one year of nursing theory.
I'm sure there are some nurses on here who have gotten their RN, BSN, MSN, etc. after starting out as an LPN both in a physical classroom and via the online nursing degree route.
Maybe we can hear from them.