I think a combination of the old 638 & 777 would make for a great road run.

The trip would start at Sunderland Interchange going via Sunderland Royal Hospital, Grindon Mill & Hastings Hill, with the (first photo stop of the run being at Herrington Country Park/Penshaw Monument), we would then continue along the route via Fatfield, Rickleton, Lambton (Quick Photo Stop) just so I can a few shots of 4855 and 4710 on my doorstep, Washington Galleries & Blackfell, then we would run through Springwell, Wrekenton and Harlow Green to the Angel of the North for (Photo Stop/Break). 

After that we would go through Low Fell & Gateshead to Newcastle Pilgrim Street to finish the 777 section of the trip with a (Quick Photo Stop), we would then head of Newcastle via Central Station and over Redheugh Bridge to Whickham where we will rejoin the 638 Route, going along Whicham Highway/Front Street and down Swalwell Bank to Swallwell before heading through Blaydon and powering up Blaydon Bank to Winlaton Bus Terminus for another (Photo Stop). We would then depart Winlaton for final stretch of the run via North Street/Blaydon Bank back down to Blaydon before heading along the B6317 via Ryton to Crawcrook where we would finish up the 638.

This would mark the end of the road run before heading back home dropping off at Gateshead and Washington Galleries only on the return trip.

Pickup Points - Sunderland Interchange, Washington Galleries, Gateshead Interchange & Newcastle Pilgrim Street

Return Drop Off Points - Gateshead Interchange and Washington Galleries (Numerous Services to connect to return Home)

Photo Stops - Herrington Country Park/Penshaw Monument - Lambton Village Centre - Angel of the North - Newcastle Pilgrim Street - Winlaton & Crawcrook
Maybe room for a few other stops along the run at scenic locations.