Head-on war would be tricky against the top 2 difficulty level opponents (unless you avoid war with diplomacy), but... with lucky start position (remote + choke points) + terraforming spells, you could isolate yourself enough to give you time to get to volcano spell + nuke every other faction on the map

Tuidjy has some great posts on here doing playthroughs of ridiculous.

where are the videos..

Ridiculous: you need some abuses, in a form of combos like blind+lots of dodge (best), or super powerful and low cost fireball on very high initiative mage, and lots of luck (drops, heroes, not being attacked by too many AIs etc.). One thing i also realize that actually you have to win a war early on, turtle-like style of play ultimately hurts you in a long run, since without AI's conquered cities your development is painfully slow ... Whereas if you get couple 5lvl cities (while you have lvl 2 at best) it is a great boost to your nation.

I have beaten 5 AI on ridiculous on large getting ready for 7

Insane - i will not even start ...

It's turn 60 on the last ridiculous game I've played - I'm hemmed in between Yithril and Kraxis and I've just conceded the game after Yithril attacked me with an epic army that includes 9 units and 2 juggernauts plus another army with a further 2 juggernauts. The third faction is Altar and they have just discovered higher education.

I think they must get some crazy high bonuses on this setting - Yithril are particularly annoying