Just for fun, I put into the gps "Pattaya to Chiang Mai quickest way".
817km - this is what "it" thinks:
View attachment 13952
1. Eastern Railway (Chachoengsao-Sattahip) 0 m 0:00:00 N12.96775 E100.92250
2. Get on Liap Thang Rotfai Rd. and drive northeast 28 m 28 m 0:00:00 0:00:00 115° true N12.96764 E100.92273
3. Turn left onto Highway 36 3.7 km 3.7 km 0:03:23 0:03:23 15° true N12.99846 E100.93380
4. Keep right onto Highway 36 4.2 km 481 m 0:00:31 0:03:54 314° true N13.00133 E100.93071
5. Keep right onto Highway 3 4.5 km 336 m 0:00:11 0:04:05 6° true N13.00361 E100.92985
6. Keep left onto Highway 36 4.8 km 332 m 0:00:13 0:04:18 158° true N13.00185 E100.93131
7. Keep left onto Highway 36 10.7 km 5.9 km 0:03:15 0:07:33 128° true N12.96992 E100.97380
8. Keep left onto Highway 36 11.2 km 528 m 0:00:26 0:07:59 117° true N12.96782 E100.97809
9. Keep right onto Highway 7 27.3 km 16.1 km 0:09:11 0:17:10 348° true N13.10720 E100.98719
10. Bear right onto (Overpass) Highway 7 28.2 km 854 m 0:00:28 0:17:38 348° true N13.11471 E100.98560
11. Keep right onto (Overpass) Highway 7 46.9 km 18.7 km 0:10:24 0:28:02 0° true N13.27741 E100.99049
12. Keep left onto Highway 7 48.6 km 1.6 km 0:00:55 0:28:57 11° true N13.29200 E100.99199
13. Exit left onto ramp onto Motorway 48.9 km 347 m 0:00:11 0:29:08 15° true N13.29500 E100.99281
14. Keep right onto Motorway 78.8 km 29.9 km 0:16:32 0:45:40 357° true N13.53580 E101.01156
15. Keep right onto Motorway 115 km 36.6 km 0:20:17 1:05:57 295° true N13.73128 E100.76377
16. Take the Kanchanaphisek Rd. ramp to the left towards Kanchanaphisek Rd. 121 km 5.8 km 0:03:14 1:09:11 270° true N13.73171 E100.71004
17. Take the Bang Pa-In ramp to the right towards Kanchanaphisek Rd. 122 km 325 m 0:00:16 1:09:27 271° true N13.73175 E100.70704
18. Take the Lam Luk Ka ramp to the left towards Lam Luk Ka Rd. 146 km 23.9 km 0:13:45 1:23:12 11° true N13.92487 E100.70588
19. Keep right onto Kanchanaphisek Rd. ramp 146 km 454 m 0:00:15 1:23:27 12° true N13.92886 E100.70673
20. Take the Ayutthaya ramp to the left towards Highway 1 176 km 30.1 km 0:16:40 1:40:07 331° true N14.18206 E100.64065
21. Keep left onto Highway 1 Frontage Rd. ramp 177 km 792 m 0:00:27 1:40:34 331° true N14.18820 E100.63695
22. Continue on Highway 1 Frontage Rd. ramp 177 km 141 m 0:00:05 1:40:39 290° true N14.18863 E100.63575
23. Keep right onto (Entrance) Highway 1 Frontage Rd. 177 km 519 m 0:00:24 1:41:03 241° true N14.18661 E100.63146
24. Turn left onto Ayutthaya/Amphoe Bang Bua Thong towards Highway 1 178 km 835 m 0:00:30 1:41:33 241° true N14.18309 E100.62464
25. Keep left onto (Overpass) Highway 1 Frontage Rd. 179 km 427 m 0:00:22 1:41:55 237° true N14.18095 E100.62138
26. Keep left onto Highway 1 Frontage Rd. 180 km 1.3 km 0:00:58 1:42:53 205° true N14.17142 E100.61661
27. Keep right onto Highway 32 183 km 2.6 km 0:01:36 1:44:29 341° true N14.18931 E100.61125
28. Keep right onto Highway 32 195 km 12.5 km 0:06:56 1:51:25 0° true N14.30128 E100.61309
29. Keep right onto Highway 32 199 km 3.6 km 0:02:13 1:53:38 0° true N14.33394 E100.61301
30. Keep right onto Highway 32 230 km 31.6 km 0:17:47 2:11:25 328° true N14.57808 E100.48568
31. Keep right onto Highway 32 265 km 34.2 km 0:18:54 2:30:19 340° true N14.87060 E100.43839
32. Keep right onto Highway 32 312 km 47.6 km 0:26:21 2:56:40 337° true N15.22941 E100.20879
33. Keep right onto Highway 1 335 km 23.1 km 0:12:49 3:09:29 355° true N15.42541 E100.14441
34. Keep left onto Highway 122 (Bypass) 357 km 21.6 km 0:11:55 3:21:24 358° true N15.61243 E100.12115
35. Keep left onto Highway 1 372 km 14.7 km 0:08:07 3:29:31 359° true N15.71732 E100.05811
36. Keep right onto Highway 1 413 km 41.1 km 0:22:42 3:52:13 317° true N15.99249 E99.81178
37. Keep right onto Highway 1 463 km 50.6 km 0:28:02 4:20:15 316° true N16.35405 E99.57896
38. Keep right onto Highway 1 481 km 18.1 km 0:10:01 4:30:16 3° true N16.47717 E99.49648
39. Keep left onto Highway 1 546 km 64.6 km 0:36:04 5:06:20 62° true N16.86311 E99.13745
40. Turn left onto Phahon Yothin Rd. 724 km 178 km 1:40:24 6:46:44 44° true N18.25353 E99.45558
41. Keep left onto Highway Lampang-Chiang Mai Rd. 725 km 1.8 km 0:01:36 6:48:20 35° true N18.26653 E99.46519
42. Keep right onto (Overpass) Highway 11 794 km 69.0 km 0:39:54 7:28:14 350° true N18.58591 E99.04209
43. Keep right onto Highway 11 813 km 18.7 km 0:10:23 7:38:37 344° true N18.75066 E99.03274
44. Bear left onto (Exit) Highway 11 Frontage Rd. 816 km 2.5 km 0:01:27 7:40:04 354° true N18.77289 E99.02814
45. Turn left onto Charoen Mueang Rd. 817 km 1.2 km 0:01:15 7:41:19 353° true N18.78327 E99.02660
46. Charoen Mueang Rd. 817 km 600 m 0:00:38 7:41:57 90° true N18.78460 E99.02115