Bill J - you said "I don't think you can get access to the underside of the engine to attach the cradle to it when it's setting over the axle." Yes you can. The axle channel should have oval hole areas where the bolts go that attach the cradle to the front of the engine. (Make sure you have a good look at those oval holes. Sometimes there is a crack in the axle channel from the hole on the left side going across and down the channel - if it is make sure you get it welded up). My suggestion, to save you alot of knuckle busting, multiple word phrases, etc., and since you're going to work over the front axle channel anyway, once you have the axle channel tightened up so the axle fits snug, just leave the axle off until you get the cradle and engine re-installed. You'll save yourself alot difficulty getting at the bolts if you had the axle installed. To get at the bolts with the axle still installed you have to jack the frame up with the tires off the ground such that when you push down on one tire it will almost touch the ground. This gives you access to the bolt hole on that side of the channel. You have to make sure you block the axle before you stick your fingers in there to put the bolt in place or you risk getting them pinched/squished.
Hydro Harry
Old Cubs Never Die (and there sometimes more than one way to put them back together)