If you're happy for up to 20-30 mins a trip, WG hotspots like Earl's Court/South Ken and Paddington/Bayswater are all well within reach.
For any SP that does catch your attention, you can check out if they have prior feedback on these forums before making your decision. Alternatively if you have some idea for the type of punt you'd like, I'm sure members here would be more than happy to make a recommendation.