Yes, you have the right idea. First thing to do would be to turn on the routing engine. Then each VLAN that needs to route needs an IP address associated with it. Probably set DHCP forwarding for each VLAN as well to point to your DHCP server. And make sure you are using newer code that fixed the DHCP forwarding bugs. Then just define a new VLAN that exists between just between the sites and give each side an IP address on that VLAN. I like to use .1 and .10 on interconnection networks and make the subnet in the 172.16.x.x subnet so if you traceroute it is obviously moving over a WAN link. On small networks I like to use RIP-2 for routing instead of static routing, but it's up to you. Each router/switch will know about it's directly connected subnets, it's just a matter of either turning on RIP-2 on the networks or adding static routes for the subnets at the other site and pointing them across the WAN. Don't forget to add a default route or have a device advertising the default.
And yes, you can use VLAN 10 and VLAN 100 at each site as long as they have unique IP addresses associated with them. So at site #1 you have VLAN 10 w/192.168.10.1/24 and VLAN 100 w/192.168.100.1/24. At site #2 you have VLAN 10 w/192.168.11.1/24 and VLAN 100 w/192.168.101.1/24