I'm gonna start doing something about this, cause it still seems like FUN side-category. @Molotok - if you have any interesting notes about routes or certain KFs post them here please ;)

I don´t have a route, but you can watch my frenzy guide on youtube. Not every frenzy is particularly done the fastest way, but I was aiming at reliability since it is a guide.

Edit: Just a note about the tank frenzy where WordofWind said it is unreliable and has a fail rate of like 1/1.1 times. I just did it 11 times in a row and got tired.. i take back the 1/5 fail rate i estimated, this is simply idiot proof. I will upload a video here soon and write some more notes.

This is what me and wind kinda came up with for downtown. http://imgur.com/a/jhMw0

Here the vid for the tank frenzy in the south-east: https://www.dropbox.com/s/11s6qu9yf4uf70m/tank_frenzy_11times.avi?dl=0 Please watch carefully, especially Wind. Use the black lantern or whatever it is as an orientation point. Align the tank cannon like I did, then drive back and forth past that lantern. Shoot when you see people approaching the wall and maybe a second time when you start to go forth again, that is it. Also starting it with a low wanted level or none might help even more with the spawns.

About the route: It looks like if you die somewhere around 8 you spawn close to 9, just south of the green Zaibatsu phones where you can take the Beamer. If you suicide with the last rocket while doing 9 you respawn right next to 13. So for that section 8(wasted)-9(wasted or busted)-13-14-11-12-10-15 looks good imo. Then I would proceed with 15-17-16-19-18-20. You can run from 15 to 17 while you shoot peds. And you can drive over peds on the way from 16 to 19. Stay with the tank not far from 18. With 18 you need to drive over a lot of peds, so you can pass more distance and reach further frenzies while driving over people. About 1 and 2 not sure, they are also close to a respawn place.

Edit: My route would be 1-2-6-4-5-3-7-8(death warp)-9(busted/death warp)-13-14-11-12-10-15-17-16-19-18-20 Did a test run on it, failed the tank frenzy in the west (need to figure up a better way to end up nearby 18) and the time was ~19:30 mins. In order to spawn at the right place after 8 I need to death warp (throw molotov while you enter car) right above the road above the police station. You collect the molotovs after starting 3 and going to the police station in the north.

Your route seems pretty decent, so I made another pic here http://imgur.com/a/vbDyb

Also protip to everyone, don't miss a frenzy Kappa

Here a demonstration as promised: https://www.dropbox.com/s/b42j4ogmu12v5z5/gta2_dd_18_37_frenzies.avi?dl=0