I am hoping to cycle from Tha Wang Pha (Nan province) west along hwy 1082 and then finding a road or trail across to Khun Khuan in Phayao province. Anyone know of a road/trail that makes the connection?  Thank you

2 alternatives for the trip from Tha Wang Pha to Khun Khuan:

One is the "standard" tour on #1082: 82 km, with 3 main peaks (1'200m, 1'000m, 1'100m), alltogether a little bit less than 3'000 m climbing work. No accomodation (afaik)! Can have some rude truck/bus traffic.
At the end the #1082 will lead into #1228 reaching Khun Khuan.

The second one is the northern one through the woods: #1148 north, about 1 km before little Ban Nam Mong turn left on #4011, after exactly 12.8 kms turn right on a (off-)road without number which will after 31kms and over the peak lead into #1188 to Khun Khuan. Also 82 km, 1 hefty climb from 400m to almost 1'200 m a.s.l., alltogether about 2'500 m climbing, almost no/only local traffic. No regular accomodation for sure, no food/beverage supply. Definitely MTB only!

At this time of the year it will be on both routes partially really chilly, sometimes foggy, until 11:00 a.m., so be prepared. This is the reason why I would not ride it before March: You hardly can start early enough to have enough time to make it (if at all; both routes are really hard work, at least for me ...) conveniently in one day.
In case you are interested in getting a file for the second, quite adventurous but very nice version write me a short PM and tell me the best file format for your purposes.
The first version you'll find easily on any map.

Great info- exactly what I was hoping for! Plenty to consider. Thank you VERY much!!