I don't know of any issues going directly to MR3 to MR4 MP2 directly.  I would upgrade the console first and then use either SEP to push the packages out via the Client Packages tab or use what ever other means of Software deployment you might have at your hands.  All depends on the granularity of control that you would like to have. 

Also go for testing first and then upgrade a few clients before and not pushing for the bigbang...
Although we had not had any issues in migrating each one has its first..
thanks...

I am currently running version 11.0.3001.2224. Do I need to wait until EVERY client is upgraded to MR4 before upgrading and pushing out MR4mp2 client? 90% of my machines are portable, and the time it will take to have ALL clients updated is going to be very long.

What options do I have for the end user to get the updated managed clients when NOT connected to the network?

In the event that I upgrade the console and start the push of MR4 to end clients, will the MR4 console support the MR3 clients? 

Can the MR3 clients be upgraded to MR4mp2 directly?

WIll the MR4mp2 console support the MR3 clients?

Will the MR4mp2 console support the MR4 clients?

 MR3 to MR4 and after MR to MR4 MP2

@eddy_frazer -I understand your concern but its the better way of doing it.
Coz if you are planning to do it viaUpgrade groups with package..it wont work and it might even create a new issue altogether...however if you are exporting a package and deploying it ..It should be fine
So what i would suggest is upgrade SEPM to Mr4 then MR4MP2.
Export a client install package for Mr4Mp2 on few clients for testing if everything goes well then start deployment for the rest.As SEP is very environmental product so it might work in my Env. but it might fail in yours so its always advised to test it..if you are doing anything not recommended.

@FinlandRobert -- 
Can the MR3 clients be upgraded to MR4mp2 directly?
By pushing package yes..But by Upgrade groups with package-NO

WIll the MR4mp2 console support the MR3 clients?
Yes ..it is backward compatible.SEPM Mr4Mp2 can support MR1-2-3 and the MPs clients as well and SEPM MR1-2-3 and MPs can support Mr4MP2 clients as well.But it is not recommended

Will the MR4mp2 console support the MR4 clients?
Same as above

Since you have all laptops you can export the MR4MP2 package and sent it via Cd or put it on a shared drive for them to upgrade.

Do not use "Upgrade gorups with package" Feature to upgrade from MR3 to MR4MP2
and yes..do test it before deployment.

better upgrade by steps rather than go for a big time jump from MR3 to MR4 MP2 directly...
Thanks...