It does not matter where you obtain your RN provided they are an accredited program. It would be highly unusual to se a local CC, state college or university NOT having an accredited program.
Yes, once you obtain your pre-reqs for nursing school and complete your ADN, it is usually 4 years. 2 years of pre-reqs, 2 years of core nursing.
Yes, you can wait on your BSN and do it later. As I stated there are VERY inexpensive options for BSN and to be competitive it will help. There are a ton of "for profit" ASN to BSN programs...they can cost you a TON of money. Avoid those. I found a local CC offering one very inexpensively and I qualified for federal loans for it.
Knowing these time scales and costs, you can see why trying to go medic route as a plan is really not best. There is no tremendous added value taking that pathway, only added debt, lost time, distractions.