While changing the intake gasket can be a big job, for the uninitiated, it is not impossible and only requires some metric hand tools. Before you commit to it though, try this instead. Disconnect battery ground, remove both front engine steady mounts, remove the upper intake manifold and use a cheap ratchet tie-down strap to pull the engine as far forward as you can get it. Don't fret, this is all easy stuff, but pay attention to clearances so you do not bind or break anything. It's not likely you will but just play it safe. Now take a wrench or socket, whichever works best, and tighten down the lower intake manifold.
I would bet that you will find many of the bolts to be very loose. Screw the manual on the tightening torque and just snug them up real well. This does not mean as hard as you can manage to reef it! Use a bit of judicious restraint. Put it back together.
If you have enough water in the oil to make it all foamy then you should change the oil before proceeding further. If you let the rig set overnight any free water will drain to the bottom of the pan and you can pull the plug only enough to let the water out, stop when you see unpolluted oil start to drain. If it is not too bad then drain and flush the rad and refill only with water.
Now take it out for a drive and stop every few miles to see if it is still heating up and foaming the oil. If not then keep driving until all of the moisture is gone. It may not take too long as the heat and crankcase vacuum will make short evacuation of what water remains. If you still have a problem, but much lessened, then you can try a good quality Block Seal compound found at many auto parts stores. Follow the directions closely and you will be surprised at the results you get.
Of course the direction you take is totally up to you, this is what I would do and the cost of it is way less than what the gasket change would be. What do you have to loose?
Here is a pic of what a worst scenario would look like and it did seal effectively, with out being tightened, It did eventually fail again but I drove it many thousands of miles before it did. Had I known to tighten the manifold too I doubt if it would have failed at all.
If you try this, and are successful, don't forget to add anti-freeze for the winter!
Brad