Joni, the best way I've found is to follow your favorites on Twitter. Most of the active ones are good about Tweeting each day's location. (I kept a Twitter list of food trucks for a while ...
https://twitter.com/RobinGarr/lists/hotbytesfoodtrucks ...
but things changed so often that I didn't have the time or enthusiasm to keep it up to date. You can look at it for some info, but there are probably tons of new trucks I haven't added. If you know of any, let me know and I'll put them on.)
I assume you don't mean Longshot Lobsta? Their Twitter @longshotlobsta has been silent since April 15.
Longshot Lobsta, at which time they Tweeted, "If you are on Bardstown Road this beautiful day come see us at the 1500 block!!" So you can see how Twitter is useful if you can find the trucks you like.