MarketPress - Wordpress user roles - shopper vs store owner

Running Multisite with Marketpress and Gridmarket
I’m making great progress with my new marketplace, but I’ve run into what I think is a simple problem I can’t solve. When a new person chooses to register for my marketplace of stores, they are given two options. Either “I want to set up a store” OR “I just want to browse.” See lines at about 253 - 276 in custom-wpsignup.php (I modified the language a bit).
When they choose set up a store, all works well. When then choose “just browse” they get login credentials as they should. But this login takes them to an empty WP dashboard. They should never see a WP dashboard. Instead they should go directly to my global Marketplace site. I believe this has to do with their WP user role. I believe Marketpress assigns subscriber to the shopper and administrator to a store (subsite) owner. Please correct me if I’m wrong.
I do have the User Role Editor plugin installed but have not network activated or configured it yet. I plan to go to Pro version of URE to restrict capabilities of store owners. However, I first need to make sure subscribers (shoppers) are taken directly to my marketplace of stores when they log in and not to an empty WP dashboard .
Thanks for your help!