Whats the easiest way to get to the tach bulbs? One side is out on my tach?

I don't think there's an easy way... just hard and harder.

I can reach a couple of the tach bulbs by removing the lower steering column cover, headlight door override bracket, and vent duct. I can then kinda squeeze my hand up under there and feel around until I find the bulb sockets. It helps to remove the seat and lay on the floor looking up under there with a light so you're not tugging on the turn signal indicator wire, etc.

Pray the socket doesn't come off the wire when you're groping around in there. I've had to re-solder nearly every gauge cluster bulb socket at one point or another. Be gentle. After 45 years, they're really fragile. Honestly, I should have replaced them all with the rubber194 bulb sockets like you find in the side marker lamps, but I already had enough on my to-do list and didn't want to add more stuff that wasn't going to get the car back on the road.

That's the least hard way. The other way, you have to remove the driver side dash panel (and all the other stuff that has to come out first - steering column, center gauge cluster, etc. etc. etc). At least you can see what you're doing when it's apart.

Aside from pulling out the heater core or AC evaporator, I can't think of a worse job than removing the dash on these cars. Sorry, I wish I had better news.

Have you considered not driving at night? 🤪

Thanks for your reply.

Looks like too much of a project. I'll wait until I need to get back there for something else..I'm startring to figure out why the things that need attention has not been done..(Too big of a pain!)

I just replaced all of my dash bulbs with LED’s

i took the front plastic off the speedometer and tachometer, then used a long set of needle nose pliers with electrical tape on the tips to remove old bulbs. Pull straight out DO NOT TWIST or the little plastic holders connected to the printed circuit behind the tach and speedometer can be damaged. 
RULE NUMBER ONE : DISCONNECT THE BATTERY 

BECAUSE THE PRINTED CIRCUIT CAN EASILY BE DAMAGED !!!!    As me how I know 🤦‍♂️

79 dash is different from a 77 and earlier.