**Please note that this is not recommended under any circumstance**
If you always want the multiple shipping address cart page to show instead of your regular cart, you can add this to your theme.liquid file:
var gs_exp_date = new Date();
gs_exp_date.setTime(gs_exp_date.getTime() + (7*24*60*60*1000));
gs_exp_date = " expires=" + gs_exp_date.toUTCString();
document.cookie = "current_ms_state=ms_cart;" + gs_exp_date + "; path=/";
You must change all links to the cart page from "/cart" to "/a/gs/cart/". The final url must have the closing "/" in order to work.
This will allow for the multiple shipping address feature to always be used.