Personally I find regional QNH to be fairly useless. If you don't want to use 1013 - and I don't bother if I'm just farting around aka enjoying flying - then I would recommend using the QNH of any airfield near your track (within 25nm if you want to be correct), and I would further recommend using ATIS broadcasts to get them as you don't have to bother making R/T calls then.