Can anyone advise the best way from Guangzhou airport to the Riverside Hostel on shamian Island?

The best way for you is to take the airport express bus line 3 and get off at Fangcun Bus Station, then catch a taxi to the hotel. The taxi fare is about CNY10.

best, quickest and cheapest (8 Yuan) way is to use the metro rail system. departs from airport and book to Fangcun station. (One change - just check the rail system maps at each station. Fangcun is on line1 - yellow.) From Fangcun take LU Lui Rd exit (B2) at end of Lu Lui turn right and walk about 300m.