Welcome to the OptoForums! Yes, you could try this out with PAC Sim. The chart uses a udp comm handle which is not yet officially supported, but it's how we talk to all the I/O Units, and works in PAC Sim, SoftPAC, -R1, -R2, -S1, etc.
When you configure your SNMP devices, just send the traps to that IP address of the PC running PAC Sim.
As Fernando mentioned, SNMP is NOT simple, otherwise we might've done a kit. You'll notice my example only parses part of the trap packets coming in. I'm hoping you'll only need a little bit if info that's easy to pick out from the traps. Normally the info you want is at the very end of the received string.
I did once write some OptoScript to do a "get" of one piece of SNMP info I needed, but it was not pretty. Essentially I just did a wireshark sniff of the packet my Windows MIB Browser sent, built that same packet in OptoScript, then figured out which byte coming back was the one I needed. Pretty brute force and not something I'd normally recommend.