2bentspokes

Hi Folks, I am lucky enough to have 9 acre wood and river area to mess about in but to be social I don't want to upset the neighbours so am looking for a "quiet" choice of bike. 2stroke or 4? 125 or 250? Any suggestions? I am new to this cracking sport though I have done a bit of off roading centuries ago! and have been on and off road bikes for 30 years or so.Thanks.