Well, You do not have to remove the Intake Manifold (at least not on my 90 Ranger), but it is very difficult to get at two of the plugs that are under the manifold. I usually end up using a Universal joint between the Spark Plug Socket and the 10" extension that is attached to the ratchet. Some Spark Plug Sockets have a Universal Joint Attached to them (I like these better).
Anyhow, If it is like mine you may need a pair of long Needlenose pliers (maybe 12" length) to reach in and remove the wires from the plugs. Be careful and try to rotate the wire on the plug to break it free, then carefully pull on the wire as you rotate it (that reminds me to buy a good spark plug wire removal tool). I also remove the alternator; this allows me to access the front plug and gives me a bit more room to see what I'm doing.
Using the ratchet & socket, I reach in between the Intake Manifold runners to remove one of the difficult plugs (3rd one back from the front). To reach the furthest plug I remove the pipe that connects the EGR Valve to the Exhaust; I do this at the Exhaust because I cannot get a wrench to turn at the EGR Valve End of things.
Then I unplug anything that is in the way of the EGR Valve and I remove both EGR Valve Bolts and the valve from the engine. This allows me a little space between the engine & firewall so that I can get the back plug out. This all takes me alot of time (I usually spend 3-4 hours changing plugs & sometimes wires too), one of my problems is that I have fat fingers (about size 16 ring).

You may need to attach a short piece of vacuum hose to end of the new plug before installing. This allows you to more easily feed the plug into the hole. Rotate the vacuum hose to start the plug into the hole and avoid crossthreading.

It is pretty difficult for me to change plugs, but I always manage to get it done.

Perhaps some better suggestions or advice can be obtained from others on this excellent website.

Best of luck to you

Gary