If you are using Particle Mesh devices with Blynk here are a few things that might help to know…
First, Blynk works great with the Boron and Argon. The Xenon is where you may run into a stumbling block. The Xenon will communicate with the mesh’s gateway and other devices in the same mesh network but they can not connect directly to Blynk. This is due to network protocol limitations over mesh networking. It will however work if you are using an Ethernet Featherwing on the Xenon.
More info about that here - Mesh Network Protocol
And here - udp-and-tcp-in-mesh
The simple solution is to setup your mesh gateway with Blynk and have it Publish events that the Xenon subscribes to. Being the Xenon can communicate with the Particle cloud with no problem it will be able to Publish and Subscribe. As well using cloud functions and variables that the gateway device can take to Blynk.
Now what would be REALLY cool is if Particle had their own dashboards of widgets.