You asked ALOT of questions here, but let's see what I can do
Getting an LVN at one school and then going to another school to begin an RN program does not get you through the RN program faster, or with less classes. Most, if not all, of the time you need the exact same classes whether you have an LVN license or not. Sometimes, you can get a pass on the fundamentals classes (basic nursing skills) with passing a competency test (if you have an LPN/LVN), but oftentimes, not.
You will not be able to get out of any of the science requirements, or any of the other degree requirements, for an RN. Your LVN is a nursing certificate program, not a degree. The community college will confer a degree in nursing, and will expect you to pass all the requirements, regardless of the LVN designation.
You will be required to pass the minimum mathematic standards, which is usually either algebra, or some comparable math curriculum. Not every college requires algebra specifically, but you should not expect the healthcare-required math to be easier. But rather than focusing on what you COULDN'T do years ago, why not approach it as you WILL do it this time, and arrange for tutoring as needed? I was AWFUL in algebra many years before I enrolled in nursing school. And yet I finished that course with the second highest grade, a 98.6. How? I REALLY wanted it that time!
Consideration for gas and mileage is only relevant if you're comparing two similar programs. You're not. LPN/LVN will allow you to do certain jobs, but not all the opportunities an RN will provide. However, if you already know you would like to work in an LPN capacity, and don't really need an RN for those jobs, then you have an answer there. But if you want a wider field of opportunity, ones that having an RN will afford, then I'd skip the LPN program entirely. It's a VERY expensive LPN program, compared with a community college degree.
Now, if you're just not sure that nursing is right for you, you'd do FAR FAR better to get yourself a CNA certification, and start working in a hospital or nursing home (or both) to see what nurses and aides actually do. In a nursing home, you'd see what the LPNs are doing. In a hospital, the RNs. I break it down like that because in most places, you'll find the bulk of RNs in acute care settings, and LPNs in long term care. Of course not always, but that's a pretty safe bet.
As for the rest of your questions, it seems to me that your choice isn't really between an LPN and an RN, is it? Mostly, it's just whether you want to be a nurse or something else....radiology tech, MRI work, NONE of that is remotely close to what either license of nursing does. If it's just a higher paycheck you're after, please think long and hard about these choices, because you absolutely won't be happy as a nurse (regardless of paycheck) if you just don't want to do it EXCEPT for the money. Lots of people enroll because of the promise of good wages, and leave promptly because of the kind of work expected. It's not glamorous, it's not easy, it's not clean, it doesn't smell good. Hours can be bad, schedules bad, holiday and weekend time expected. Respect is sketchy, toll on the body considerable. All that said, if you go the CNA route and decide you want in, well, compare the options the LPN and RN will give you, and jump on in!