You can also just download Arduino and Teensyduino for free, open some of the example and click Verify. The Arduino IDE prints a summary of the memory used.
Maybe take whatever libraries and code you're intending to use and throw them together into a test. Using "volatile" on variables is a good way to prevent the compiler from noticing your inputs are constants and optimizing away much of the code. While you need the hardware to actually run the code, this can at least give you an idea if the 62K of flash is enough.
Typically the 8K RAM size on Teensy LC becomes a limiting factor before the flash fills up, but it really depends on which libraries you use and whether your code needs to allocate any big arrays for data.