Hi MKB, welcome to Dooney! You came to the right place. I'm sure you'll get lots of suggestions here. The first bag that comes to mind when I think of a Dooney hobo is the infamous Logo Lock hobo from QVC. It comes in lots of colors and it's a large hobo. It's great for all weather and it comes with some accessories if you get it new. If you pick one up "as is" you risk not getting the accessories but you can call and ask ft an additional discount. Here are some links.
http://www.qvc.com/Dooney-&-Bourke-Leather-Hobo-with-Logo-Lock-and-Accessories.product.A203807.html?sc=A203807-Tailored&cm_sp=VIEWPOSITION-_-1-_-A203807&catentryImage=http://images.qvc.com/is/image/a/07/a203807.001?$uslarge$
Here is another great hobo that's exclusive to QVC, but this Sophie silhouette is also available in Dooney.com, ilovedooney I think, and the outlets, but without the color block black trim.
http://www.qvc.com/Dooney-&-Bourke-European-Leather-Sophie-Hobo-w-Accessories.product.A259485.html?sc=A259485-Tailored&cm_sp=VIEWPOSITION-_-18-_-A259485&catentryImage=http://images.qvc.com/is/image/a/85/a259485.001?$uslarge$
If you search "as is Dooney & Bourke" on QVC you often will see these pop up there for around $100 less and sometimes also on easy pay.
These are two great large hobos that are great for any kind of weather.
Good luck!