Hi, Brian!
"Split stays" between two
resorts is fairly common among guests at Walt Disney World. As long as both resorts are on property, Bell Services will be happy to transfer your luggage to your new "home" so drop your bags as you check-out of your resort.
With your plan, your tickets will be good for your entire stay.
Tickets are valid for 14 days after their first use so use your tickets however you wish. The
Disney Dining Plan is different. If you have the
Magic Your Way package for your first resort (room/tickets/dining) then you must use all of your credits by midnight of the day you check out of that first resort.
Read through the details of the Magic Your Way package or call a friendly Cast Member at (407)934-7639 for more information.
Budget wise, it might make more sense to select one resort (perhaps a less expensive one) and add on the "base" Disney Dining Plan. This way you are covered for your entire stay.
I hope you find the perfect vacation plan that fits your family's plans. Good luck!
Cathy