2000 F-150 Bi-Fuel - Intake Manifold Gasket

Good morning! I've been a long time user of this forum with my 2002 Ford Windstar and it's myriad of troubles, but have rarely had to visit on account of my 2000 F-150 that has behaved so well over the years :-) I believe I have a problem with my Intake Manifold Gasket. After a long road trip on Saturday, I parked the truck and it suddenly started spewing fluids all over my driveway. Turns out it was coolant and oil. I've had two mechanically savvy people look at it, and both agree I need to start with the IMG. I have done some engine work on my windstar - I replaced the isolator bolts in the motor based on a walk through I found here, so I'm wondering if this is something I might be able to deal with on my own. My truck is a bi-fuel CNG engine, I do not know what level of complication that will add to the process. Can anybody point me in the right direction please? Thanks! Farns