I guess I"m thinking too much in my box. Our worship team tends to use at least a chord fake sheet (guitar / keyboard chords written over lyrics). That's all I need and I'm good to go.
There was a time last summer when a few of us played with a southern gospel pianist who was really good at that rhythmic bluesy, southern gospel, honky-tonk type of genre. He was quite free-form in his playing.
He didn't use music at all, but the guitarist and I requested that he give us something to at least put us "in the postal code". All we got was something like "Ab-Db-Eb-Ab" which we scribbled down. The whole set filled all of half a page. But you know what? It was enough. It was a fun instrumental gig and the congregation really got into it.
I'm sure your keyboardist could put together something like that. He's probably only got about a half dozen licks he uses most of the time anyway. Seems like it would take no time at all for him to write down some progressions that you could have handy and practice from, knowing that they were going to show up at some time in the service. Otherwise you're going to take a while to latch on to his favourite hooks, riffs and progressions.
Alternatively, if your church records your services, grab a couple of tapes and listen to them. I'm sure you'll find those favourite hooks and progressions in no time at all and you can practice them and be ready for the next time the keyboardist rolls them out. Or, if you don't record your services you could buy one of those cheap digital recorders and record your songs. I used to use one when I first started playing. I'd record songs in Thursday nite practice and play along to them before Sunday service. Even though it was low-fi I had everything I needed to get my lines together.
Maybe it's just me, but I think your situation is kinda backwards. Bass does not "follow" the keyboard, it drives the song and the melodic and harmonic instruments sit on top of the foundation that's created. They have to "keep up" with YOU and the drummer, not the other way around. You just need to know the general direction of the road then you can use the accelerator, brake and steering wheel to keep it between the shoulders. It's about unity.
All this is moot if you're playing in a completely unstructured, ad-lib, improvisational type of setting. I also would find that a bit challenging. It makes it kind of hard to get into the groove (nevermind create the groove) if your brain is working at 80mph just to stay in key and not make a mistake.
Key signature / Meter represent a minimum of info that you should reasonably expect to know beforehand in order to do the best job possible on the bass. "Follow me" from the keyboardist is just a little lazy and maybe even a little egotistical IMO. In the heyday of Motown a lot of the music was not written down and James Jamerson / Bob Babbit / Carol Kaye had to play without written music. HOWEVER... they did get the chance to hear the music before it was recorded so that they could compose an appropriate bassline before tape started rolling.
Personally, not that I want to create dissension among you and your bandmates, but I think it's a bit unfair of the keyboardist to play in this manner and just expect everyone else to get with it. Because you're new with the group, some may feel entitled to take the lead and expect others to follow. As your skill level increases and you have more confidence in your abilities you will be able to communicate that you expect a bit more from your bandmates to help serve the song overall. Again, this is not just to help you, but to remove some of the cranial "CPU load" so that you can concentrate more on the feel and groove of the song, and not have to use your head so much. Your expanding groove will become infectious and that benefits the whole band. Again, it's serving the song, not serving what happens to be in the head of the keyboardist at any given moment. This by definition, is almost impossible to decipher unless you've been playing together for a few years, because, as you know, you can only read minds in sci-fi movies.
Again, I'm probably referring to a situation that's more structured than yours so I apologize if I'm pontificating in a general way that doesn't fit your context. Our worship team tends to improvise relatively little (repeat a chorus, go acapella without instruments as the spirit leads, build to dynamic climax and then bring it right down again) and this tends to happen within the context of what's written on the page.
Even in a predominantly improvisational setting there is plenty of freedom for all instruments to express themselves if there is a very basic framework to build on. That basic framework doesn't quench the Spirit or the musical spirit, it just gives a simple foundation upon which everyone can musically express themselves yet still sound unified.
Maybe some of the things that have been mentioned are goals that you can aspire to at some time in the future. Maybe some you can plan to communicate sometime soon. Pray about it, and you'll know when the time is right.
b/c I need to lock with the drummer, I have been stalling them for a few months now... but the move is coming... So I gotta get myself together and stop playing copy cat with the keys...
