-
The Smoke & Dart were good tyres in their day ( when I still had all my hair ). The High Rollers can be a bit draggy, but are generally good all-rounders. Don't know what the clearance is like on your retro steed, but bigger than 2.1" may not be advised, and 26" High Rollers are no smaller than 2.1" ( no idea if they're true to size )
26" will limit your choice a bit, and most foldable tyres with any decent rubber compound will likely be tubeless, whether you need it or not.
Bontrager XR Mud ( Badger recommended ) and Specialized Storm Control are both XC light mud tyres and available in 26" .
I'd likely go for an 'all-rounder' tyre like my current favourite Vittoria Barzo Graphene tyres, although these Specialized Ground Control are going pretty cheap at Tredz, with an extra £5 voucher on top of that
TLDR - proper mud tyres will make you hate riding to the trails, so HTFU and use some Gatorskins
Do you want them for real deep sketchy mud, or mixed terrain rides?
The best mud tyres I've used have always been a real chore on the road