You're going to have a hard time with the +6 neck dragons in WW solo, and especially pulling them to a kill spot with no wanderers/adds. The +4 neck dragons should be cake though, and most of them spawn along the northern shore so it's easy to pull them to a solo spot. You'll want to focus on the ones that drop the dragonhide piece you want to sell, for example
Bravatar drops the hp/mana mantle that everyone and their twink is after. Also they drop great/greater dragon heads, which (if you have good giant faction) you can turn in for these quests:
https://wiki.project1999.com/Living_Dragons
https://wiki.project1999.com/Dragon_Heads