Front-end shake above 70 that gets worse.

Whooh! Wheele & inlienment???
Sounds more like tires to me. You say they're worn, so what's it hurt to start there? CV joints & worn bearings usually make noise @ low speeds.
Good luck!

Hi,its possible for the inner wheele bearing has broke down,just rase the wheele off the floor hold the wheele one hand at 12oclock and the other hand at 6oclock and push at the top and at the same time pull the bottom,and push and pull to see if you can feel eney playif no play thats good then spine the wheele it should spin freely(that shows that the wheele bearing is ok if it spins freely and no play it will also show you if there is eney ply in the top and bottom balljoints).
to check the trake rod end you do the same as before with the wheele but this time you hold your left hand at 9oclock and right hand at 3oclock and again push and pull this time you are feeling for movement on the right hand side(which would be trackrod end)no movement great.
I would do this on other side as well,then if every thing seems fine you will have to take it in to some where to have the traking done(wheele inlinement)but make shore that you check for worn parts first before you get traking done ,as if you replace a part you might have to get the traking done again.
Hope this was some help,all the best.

I would start with a front end alignment and new tires before I would jump to any other conclusion.