Crazy wifi connection at McDonalds

I drive around Southern California for work & stop in McDonalds to break from heavy traffic & check email. 

In a few McD's, the wifi connection works good, in other McDs, laptop sees the wifi signal - often it's "all bars", but as I access that connection, signal strength drops, THEN the system says service is "limited" - thus NO WIFI connection is made. 

I use a Lenovo laptop, Win8 (updated) & have Verizon fiber wifi at home & office; my hardware & OS are good. ... When I connect to wifi at Starbucks it works (but is often slow).

So ... how do I fix this problem for McD's? ...  Carl