Iforte,
You are on the right track to manage on PC and write to the radio. However, don't overlook the need to Front Panel Program (FPP) you radio from time to time. I like Repeaterbook as it has many ways to sort the information. Its available for smart phones when you travel outside your local area. It is not always accurate, but none of the sources are 100% and many assigned frequency pairs are not on the air and likely never will be. VHF & UHF have a offset convention that is usually followed, but not always. UHF is most often +5MHz, can't recall any that aren't. VHF convention is a little different across states, but again general follows + or - depending on where the transmitter's frequency is in the band. Repeaters that don't follow the convention are not common. Repeaterbook will have all the details you are looking for. I organize my memory channels by club affiliation and city. Club repeaters at the top followed by the closest city moving outward as the channel number increase.
Good Luck,
Mike