It will reduce your ladder weight by a factor of 3-4, but this is usually on the order of 1-2% or less of your total lander weight. It's not going to affect it as much as the heavy landing gear or the batteries/lights pack.
The only other thing your batteries would be powering is the ASAS system. I'd look into either sticking the little generator or a small solar panel to recharge your system so you can still use your ASAS.
Do batteries affect ASAS? I've used ASAS and I've never seen my battery go down.
Aww crap, I have not been paying attention at all to my engines, in terms of efficiency. One more thing to look at.
Joycoolyo, that is a strange rocket design.. or maybe mine is strange who knows
Yeah, its pretty strange. I just wing it in terms of rocket design. Whatever works

Anyways, I've fiddled with it enough that I do in fact have enough fuel to get there without using my lander's supply. Which means that I have more than enough to get there and back.
Now I just need to nail a second landing to test it out and I'm good to move on!