No need for another solvent; simply making a tea with hot water does the trick. Not boiling hot though, as it'll degrade the active components to some extent. Aim for 70 degrC before adding the ground material.

Alcohol (everclear) is a good long term storage medium for mushrooms. Tea (as suggested by another poster) works alright but loses some potency and doesn't store well.

One thing to be aware of is that you need a decent amount of everclear to perform the extraction, but once you've gotten everything out, you're going to want to reduce the alcohol by evaporating some of it so that you don't need to take several shots to get a good dose.

Also, boiling isn't a problem for mushrooms, psilocybin is heat tolerant to that level. Water, on the other hand, degrades psilocybin fairly quickly.