I think it's splitting hairs to go by estimated time for Hwy 36 vs 299, but I know that with a fresh load of fuel, I can beat the time using 36 because I won't have any traffic, police or other issues clear to I-5. The most important factor is to check for construction along both routes. Any one-lane restricted traffic will absolutely kill your running time. Hwy 299 has more speed enforcement, heavier traffic, the CHP in Weaverville, and more likely to have construction zones.
Current conditions definitely favor 299, but that can change.
Use this page and insert the route number for any road restrictions (1, 299, 44, 36)
https://www.dot.ca.gov/cgi-bin/roads.cgi?roadnumber=299&submit=Search
Use this page to keep track of planned construction that may affect you:
https://www.dot.ca.gov/hq/roadinfo/plannedwork.htm
Humboldt County
Route 36 (31.4) – Emergency work west of the McClellan Mountain Summit will continue. One-way traffic control will be in effect from 8 a.m. to 6 p.m. weekdays. Motorists should anticipate 10-minute delays. LC#C36TA
Route 36 (36/40.4) – The Federal Highway Administration will continue work west of Buck Mountain Road
will resume on Monday, January 7. One-way traffic control will be in effect 7 a.m. to 5 p.m. weekdays. Motorists should anticipate 30-minute delays. LC#C36KA
Route 101 (58.7/66) – Drainage work in Fortuna from Drake Hill Road to the Loleta Drive Overcrossing will occur from 7 p.m. to 7 a.m. starting on Thursday, January 3. Lane closures will be in effect. Motorists should anticipate minor traffic slowdowns. LC#C101XE
Route 255 (0.7) – Bridge work on the Middle Channel of the Samoa Bridge
will conclude on Friday, January 4. One-way traffic control will be in effect from 7 a.m. to 5 p.m. weekdays. Motorists should anticipate 10-minute delays. LC#C255DA
Route 299 (1.8/2.9) – The eastbound offramp to Route 200 will be fully closed for emergency work and a westbound lane will be closed from the 200 junction to the Essex Lane Undercrossing Bridge. Motorists should anticipate minor traffic slowdowns and follow signage when alternate routes are necessary. LC#T299CA
Mendocino County
Route 1 (75) – Emergency work at Blue Slide Gulch will continue. One-way traffic control will be in effect. Motorists should anticipate 5-minute delays. LC#C1TA
Route 20 (38) – Pavement work at Potter Road will occur on Friday, January 4. One-way traffic control will be in effect 7 a.m. to 5 p.m. Motorists should anticipate 5-minute delays. LC#C20FB
Route 101 (34.5/39.4) – Emergency work from Reeves Canyon Road to Ridgewood Ranch Road will continue. One-way traffic control will be in effect. Motorists should anticipate 10-minute delays. LC#C101EF
Route 101 (67/81) – Pavement work from Steele & Davidson Lane to Bell Springs Road & Road 324
will conclude on Saturday, January 5. One-way traffic control will be in effect 7 a.m. to 5 p.m. Motorists should anticipate 5-minute delays. LC#C101WD