GS724T Mixing managed and unmanaged

Hi I have created 2x Vlan using 1 trunk with 2 subnets....which works great...however some of my dumb switches dotted around my house hate the tagged vlans.....and will not work.

My solution is to have say 12 ports using vlans ie 6 on each.......then use a portion of the switch (12 ports) as dumb unmanaged  ports..... would this work.

I propose to keep my trunk for the vlans......and run another ethernet cable from a spare lan on my Draytek router to one of the 12 unmanaged ports........which should allow connectivity....aghh I think...

Would this work....if so could you advise me on configuration changes to watch out for...