I don't know if this is a simple anoyance or a bigger problem waiting to happen. There are some weird things going on with my drain vents and I have gurgling problems. Is there anything worth doing about these issues?

I really wish I could make sketches of my pipes but I'll try to talk my way through this

1) Kitchen,
The kitchen sink drains pass through the floor to the basement at this point a pipe Ts off and passes outside to what I'm assuming was intended to be a vent pipe. It sticks out off the wall and is about 3ft of ~1/4" copper pipe roughly parallel with the ground. (I would think this should be vertical not horizontal.)
The drain then goes to a main line. This is the only vent to this main line. It looks like the clean out plug to this line has an adapter in it so my untility sink & washing machine draining into it. The washer will cause gurgling in the kitchen.
I assume none of this is to code but it seems to work ok.

2) Bathroom
The main line for the bathroom looks like it goes straight up into your typical roof vent. The toilet is right there so it doesn't affect the sink and tub, but the tub and sink will cause each other to gurgle. The sink trap drops throug the floor to a pipe that T's into a pipe from the tub to the main line (no venting). The tub's pipe that the sink T's into is roughly level for about 5ft before going into a 1.5ft ~45deg connection to the main line.

It looks like this is all original from 1950 (execpt the utility sink and washer)
Should I leave well enough alone or try to "fix" some of this?