After reviewing my previous input, I glanced over the pfSense Definitive Guide and found this:
"Static routes will not route traffic over an IPsec connection, never configure static routes for any IPsec traffic except in the case of traffic initiated from pfSense itself."
And that "The only option if the subnets are not contiguous is to create parallel IPsec tunnels, 1 for each subnet."
The quoted info above can be found in section 13.4.3 (Routing multiple subnets over IPsec) of the Definitve Guide.
That said, cosolidating your existing class A and C subnets seems to be the only solution.