The Shuttle PEG rewrite is here:

• https://github.com/lamont-granquist/MechJeb2/releases

That had issues which make it not generally viable for public consumption.

A new version of that guidance is being rewritten which will do more exact trajectory calculations without the clipping issues of PEG, that will solve a lot of problem. The feature set it will ultimately target includes:

• timed launches to only LAN of target / user-entered LAN
• launches to selected keplerian coordinates, with the unselected ones being optimized.
• launch to rendezvous that works without a prelaunch
• suborbital launches to a desired altitude (and keplerian targets like inc) with the final velocity being maximized after the stage burns out
• direct ascent to a moon
• optimized coasts
• direct ascent to interplanetary (wishlist)
• node executor rewrite using that guidance under the covers
• landing guidance rewrite using that guidance under the covers (#1052)

gah, i can't believe i opened two identical epic issues, need more coffee, #1061 mostly has more detail now.