Solved FreeBSD 9.3 to 10.3 upgrade

Well after learning that 9.3 is no longer supported I finally took the plunge and decided to upgrade to 10.3

My mistake I think was to try and do this remotely. Everything went fine and duly rebooted using shutdown -r now, but the server has not rebooted as nothing can be accessed and pinging the IP address of the server from the router returns 5 failed pings.

It is using the GENERIC kernel so assumed it would reboot without a problem. I cannot get onsite until tomorrow morning and I realise this is going to be a needle in a haystack question but is there anything obvious I may be missing here or should look for when I get there ?
It may depend from your settings, but when I upgraded my 9.3 vps (under Xen) to 10.x last week I noticed that re0 interface name was changed to xn0.
Maybe it is not the same in your case but I would check console messages. dmesg, network interface (if it is under Xen) etc.
My mistake I think was to try and do this remotely.
I do this all the time. All our servers are accessible with IPMI or a (networked) KVM switch though. Which is always a good idea to have.
If you have a few other servers to do, try setting the network configuration like this:
ifconfig_DEFAULT="inet ..... mask ...."
The _DEFAULT will pick the first available interface, regardless of its actual name.