Any locals with some knowledge.

In order to avoid the A19 through York I was contemplating using the cycle path from Overton to the Designer Outlet, alongside the river.

Know the bit south of the centre is/was all tarmacked.
Whats the northern section like?
Suitable for road bikes?

If I remember right, that section is used by the Way of the Roses, picking it up from lanes across at Beningbrough Hall. If it is that route, then it’s all tarmac, but winding and pretty narrow, you wouldn’t choose it as a typical route for roadies, but you’ll have no bother.

Yes but not a single continuous cycle path.
In vague terms…from Overton you’ll approach town centre with river on your right, cross pedestrian bridge to station, turn left past rowing club, then need to follow nose/road to Rowntree park with river on your left (OK for cycling), through 1 set of traffic lights. Down to & past Millenium bridge & keep on the river cycle path which soon turns right to the Knavesmire, cross road into Knavesmire, follow path for couple of miles by racecourse, past wood on right, follow signs to Planets/Selby cycle path(?), ride to Naburn & exit for Designer Outlet.

Oh looky, someone made a vid:

[video]https://www.youtube.com/watch?v=x87cIt8TXUQ[/video]

IIRC its all tarmac out of York heading towards Clifton Bridge and from there you cut away from the river through the Ings and past the back of the old mental hospital and then up towards the bypass. Under the bypass bridge and then behind the Riverside Farm pub and up to meet the A19 between the bypass and Skelton. From there I think its a path by the side of the river until you can swing a left on the back road to Overton (where my aunt and uncle live coincidentally). From where the path joins the A19 at Skelton you used to be able to cut back down to the river to Overton but this was a the riverside footpath and unless its changed in the last 10 years, certainly wasn’t road bike country!