In an uneventful friendly game Mills notched his second goal of the pre-season campaign, strolling through the defence of the Second Division side and side-footed home in the 53rd minute.
Venables said afterwards: "It was a good workout. I've had three games on tour, looking at people in different positions and I did that again today. We've got to harden up, but it's been quite pleasing - we've now had four wins against tough opposition.
"We're learning about each other and I've had the chance to talk to them all individually just to find out what their thoughts are about different things. But we've now got two weeks to get out on the training pitch every single day and really get ready for the opening day."
Leeds travel to Scotland for their next pre-season game, against Glasgow Rangers on Wednesday.
Leeds: Robinson, Mills, Harte, Dacourt (Johnson 62), Woodgate, Matteo (Radebe 68), Keane, Smith (Wilcox 62), Kewell, Bowyer.