i did it on one a few months ago, here's what i remember
1. remove front seats (not required, but worth it)
2. remove engine cover (center console inside the van)
3. i remember there was something, maybe air duct or a bracket or something thats in teh way of the middle plugs on the left head, the fuel rail does not have to be moved, just work around it
4. remove coil units from above each spark plug (one at a time is ok), an assortment of extensions and universal joints will be required.
5. use compressed air to blow any dirt or foreign matter from spark plug holes before removing them
6. apply a small amount of your favorite penetrating oil to each spark plug, if desired, to reduce the risk of plugs grabbing onto the heads. the one i did had the rear plug on the right head grab (the most accessible plug), and with large amounts of BP blaster and back-and-forth action, i safely removed it. i used a harbor-freight air ratchet for removing most of the plugs, saves time but doesn't have enough torque to get you in trouble if one sticks.
7. find an assortment of universal joints, extensions, spark plug sockets, regular deep sockets, etc. and use them as required to remove spark plugs
8. apply anti-seize to threads of new spark plugs and install in normal way
9. install coils. you're likely to experience the hold-down screw of at least one of them cross-thread into its hole. when this happens, remove the screw and either cut off 1/4" (or as needed) from the end, or replace it with a shorter screw of the same size (and wrench size)
10. install remaining components, in order of removal
11. start engine and test-run until you're confident that it won't throw a misfire code
12. enjoy a good beer
as for your concerns about clearances, thats what the universal joints are for. i'd be hopeless without them. i remember that i unbolted the fuel rail, thinking i would need to move it, but turned out being able to work around it in its original position.
IIRC, i spent about 4 hours to do plugs, coils, filters, and maybe something else. my customer was tired of coils burning out, so he asked for all new coils, and got them, even though this isn't standard procedure