RLYMN
You can have an offsite/DR site also act a functioning replication site with actual workloads on them from the production site with replication every 5-10 seconds using a product called Zerto, watched the demo and live failover and live test, amazing product but not cheap. There is a lot more that goes into it than just that plus you have to have your network setup correctly along with acceptable bandwidth/latency but it can be done without too much effort. For seamlessness you would need to be switched across your WAN (we have layer 2 fiber WAN so works great for us), routed can bring about all kinds of complications and equipment purchases, cant wait til SDN matures and makes this an ordinary/easy thing no matter how your network is setup.
In all this setup costs quite a bit of money unless you already have it in place then...