We are in Melbourne for 2 weeks in January and want to take 4 days out to travel the GOR and maybe ferry across to come back up via Mornington back to Melbourne, (or vise versa) we want to do this say 17th - 21 Jan, is accomodation going to be a problem then.
Is that trip doable in 4 days and where would be the best stopovers?

mikandsue. If you use the Search option on this forum and type in "great ocean road" you will see LOTS of reports/messages about how to enjoy that drive. It is a wonderful trip and I'm sure you will enjoy.

You'll be here in the middle of the school holidays, so you may need to be a bit flexible and/or book ahead. I've done the loop you outline a number of times and it's very doable in 4 days.

Places I've stayed in & enjoyed are Portarlington; Queenscliff; Port Fairy; Barwon Heads;Sorrento.

http://www.travelvictoria.com.au/portarlington/
http://www.travelvictoria.com.au/sorrento/

I would certainly book and it may already be difficult to find accomodation. Lorne. Torquay, Queenscliff, Sorrento and Warnambool have the most places to stay,with Lorne being the top pick. But Melbournians often book a year in advance. 4 days is sufficient.
http://www.greatoceanrd.org.au/
www.wotif.com

Definitely include Apollo Bay and Port Fairy and in case your dates change, Jan 26 is Australia Day and a public holiday.

I just returned from a great month in Australia and we spent three days on the Great Ocean Road, staying in Lorne, and the most amazing place of the entire trip, The Great Eco Lodge at Cape Otway. The only change I may have made was to stay near the 12 Apostles as we arrived in the middle of the day and in the midst of hundreds of people. It would be nice to have been there early or late in the day for magic light photos. From there, we continued to the Grampians and went back to Melbourne from there. Ideal trip for five days. Trip report to follow next week when I have time to post events of interest. Thanks to Bokhara and Alan G for all their pre-planning help.

A lot of accommodation will be gone already as it's the main school holiday period of the year, as has been pointed out by others. But that doesn't mean you won't get in somewhere. I'd try booking ahead now, use the websites given above or www.tripadvisor.com for ideas. Don't forget caravan parks have a variety of modern cabins with kitchens and bathrooms, try

http://www.big4.com.au/
http://www.toptouristparks.com.au/

If you just wing it, you may still get in but will probably be left with the very expensive or the plain awful, or possibly have to drive a lot further just to find something instead of staying at a small town you like. I've never used the ferry between Queenscliff and Sorrento but it might be a good idea to pre-book.

Have a great time.
Kay