If you don't have any issues with spending a few nights 19 kilometres outside of the city, check out the suburb of Adelaide Hills. It's got 12 available hotels, including Mount Lofty House MGallery by Sofitel and Cladich Pavilions.
For some alternatives, look at the Buxton Manor and the Barossa Shiraz Estate. They are located 30 kilometres and 20 kilometres respectively from the main center. If those two aren't the best fit, you can try the Fire Station Inn or the Adelaide DressCircle Apartments - Sussex St.
The close by cities of Cockatoo Valley and Northfield are definitely worth checking out. Cockatoo Valley is 16 kilometres to the north of Kersbrook, while Northfield is 20 kilometres to the west. Hotels in Cockatoo Valley are the Barossa Country Cottages and Belle Escapes Barossa. Northfield options are the Quest Mawson Lakes and Comfort Inn Manhattan.
Adelaide International Airport is the nearest preferred airport for arriving in Kersbrook and is 35 kilometres from the CBD. If you choose to stay nearby, try the Seawall Apartments or the Stamford Grand Adelaide.
Hotels in Kersbrook start at AU$89 per night. Prices and availability subject to change. Additional terms may apply.