How possible is it to transfer to Active Duty on the deployment from the National Guard?

You can not transfer over. When I deployed in 2009 with the NC NG that option was there and I intended to use it. While I deployed that option was taken away. There are few options to transfer only to the Regular Army when you are in the National Guard. You have to look up the "business rules". These are the rules regarding prior service joining the RA. I was a SSG at the time and I decided to go to OCS. I found it quite rewarding to commission and I am proud to have done it.

Also, with the RA downsizing they are forcing soldiers out. I don't foresee taking anymore Prior Service unless you have a MOS in a critical need.

There is one way that this can be done. The only way that I know that you can go active now is going to a college and enrolling in ROTC. If you are at the top of your class you may get a commission to the RA.

Your best bet would be to try to go AGR...

The easiest way is to reclass into an understrength MOS.

The other option is find an "application MOS" such as 35L or 12P and be accepted into their program. They have the power to move you from reserve (or NG) to active duty, however not all of these programs accept Reservists and some accept reservists but keep them in the reserves. I know that 12P will allow the transfer but that program is fairly difficult to get into and you still need to go through the conditional release process.

Going from Guard/Reserve to Active Duty depends mainly on the needs of the Army. They have the Business Rules for Recruiting which governs what prior service folks they're allowed to take. Certain things, such as Airborne qualification, generally help. But if you're MOS isn't one of the ones listed as being needed, you're pretty much out of luck. They put out a new memo every month or so I believe. So best bet is to get in contact with a Recruiter and touch base with them every month or so. But going AGR is also a great option.

First of all if you have never been on Title 10 active duty other than Basic/AIT and don't have any college you will more than likely go in at the last rank/grade on your DD-214 when you were separated from duty.

Some Army Reserve and Army National Guard soldiers who are currently activated can apply for direct transfer to active duty. You will have to go to the command you are under during active assignment and request it, there is no promise, but if you are in an MOS needed or if their unit is short they may grant it..It also depends on age, rank, and skill sets.. Also know that there is a chance you will have to drop a rank at first..

I am pretty sure that when you are deployed as NG, you are automatically put on "Active duty." I may be wrong, so i hope noone tries to throw stones at me.