If Doc's and Cara's relationship is plotted to be long-term I see Cara's getting some of the crew's lunch business as well as those late night sessions that require coffee and doughnuts to keep the crew at top form.
Howie's would still get Doc's and the crew's business when returning from the weekend paintball sessions. Especially after any of Doc's "adventures" where liquid relaxants are required before returning to the shop and civilization.
Remember that according to Doc N., Cara's is only a couple of blocks away from the shop while Howie's is miles away almost halfway between the shop and Red's paintball fields. Could cause some interesting escapades.