Travel to Chiang Rai

I guess the options are to drive or take a bus.
Information on travel time, distance, road condition, etc. will be appreciated.

Roads are fine. Time depends on how many places you want to visit on the way and the route you choose. Requires at least one overnight stay somewhere.

Shortest (in time) route. Will have two drivers.
Going to attend some religious stuff for my brother-in-law's new house near Chiang Rai.
None to minimal sightseeing.
How far is it from Udon?

I just came back from Nan. Best road is via Loei or KK, Pitsanulok, Uttaradit and then north. You can do it in a very long day, but in practical terms you should reckon two days. Guess the distance is about 700, 800 km.

Quickest Route has to be Route 210 to Wang Sapang. Cut through to the Phu Rua Road (203). Turn left, and continue past Phu Rua. The road forks (where route 203 turns South to Highway 12), and you need to take the right fork, route 2013 to Nakhon Thai. At Nakhon Thai turn right at the traffic lights (there's only one set !!) onto route 1143 headed for Chat Traken. At jn of route 1245 turn left, which brings you out onto Route 11 just South of Uttaradjt. Then it's just a matter of heading North.
The cut through at Wang Sapang is a bit tricky to describe, but easy when you are there..... when you get to the traffic lights on Route 210 (where it crosses route 201 into Loie), go straight over (don't head to Loie). In about 400 metres there is another set of lights (in Wang Sapang town), turn right here, and continue for about 2km. You pass a school on your left (big playing field), and directly after the school do a left. This road will take you to the junction with Route 203 about 15 - 20km outside Phu Rua.
I now use this route every time I head towards Chiang Mai, as It saves almost 2 hours and 100km over the route via Phitsanalok, due to the avoidence of heavy trucks on the single carriagway stretches of Route 12 (about 100km)

Did the overnight bus to Chaing Rai around Christmas time, excellent service. If you are a big chap there is not masses of legroom. The give you the normal packet of biscuits, rice and water for the trip and a hot drink is mustered up when you go over the pass about an hour outside Chaing Rai. Also note that it arrives at the bus terminus about 8km outside Chaing Rai! So its either a baht bus into town or a tuk tuk.

Was it a VIP type bus, or a step lower, but still with A/C and a small recline in the seat back. Did it have a toilet. How long did it take. I realize that I can get the answers from the bus depot, but to quote from an old TV commercial in the States, sometimes I "let the fingers do the walking".

one step down from a vip, small recline and a bog at the back to deposit gifts for the cleaners. Time 11 - 12 hrs.

Thanks.

Ended up going by a bus.
No VIP bus on this route. The best is a step lower, 4 seats in a row vs. 3 seats in a row for the VIP. Enough leg room for me at about 175 cm. Did include a toilet, but the toilet in my bus did not have water. Even this class of bus (B572, one way) is not available every day of the week. Starting at around 20-00, it was a moderately painful 13+ hours journey. Returned in the daytime in a car of a family member to Chainat, an overnight stay, and then bus to Udon with a change in Khorat.
Went over to Myanmar via Mae Sai. There was a hot spring on the way; dipped my toes in the water and burnt them before I saw that the locals were boiling eggs and bamboos for free. Shopping across the border was worthless. Wines that I knew of were hardly bargains. Even the 3% alcohol Chinese wines were not that attractive in price. On the way back, wine from Mae Sai One winery was worth a try. See another post.
Perhaps if we had went a bit deeper into Myanmar, would have found something to interest me.