[KRWolfblade]

So according to the Gaim Gaiden 2 website and on a ameblo blog entry (I don't know if it's confirmed cos its the only external link that the KR Wiki Gaim Gaiden 2 page had plus I don't know Japanese), the synopsis' for the two films are (and I'm paraphrasing):

Duke: While Ryoma is continuing research on the Sengoku Driver along with Takatora, Yggdrasill is involved in a suicide attack. When Sid and Yoko investigate, they find that the mastermind of the incident is a group called Black Linden and that one of its members, Kyokai Inudo, was a former colleague of Ryoma's and had used the Zakuro Lockseed to brainwash people. Ryoma finds this impossible as Kyokai supposedly died a long time ago in a Lockseed related incident.

Knuckle: A year after Kaito's disappearance, peace returns to Zawame City. Zack departs for New York and leaves Peko in charge of Team Baron. But Shura, a former member of Team Baron that Kaito exiled, has returned to Zawame City and forms Neo Baron, a dark parody of Team Baron. Zack returns to Zawame City to set things right.

Also a new Rider will appear in Duke's film called Kamen Rider Dictator, a pomegranate themed Armored Rider.

That's all I've seen/able to find so far, so it looks like Duke's will be set sometime before the series and Knuckle's will be set after the series with flashbacks involved.