Not sure how much you carried when backpacking, but you should be able to go lighter than 30-40 pounds. Spares and tools can be pretty minimal (a pound or so including spare tubes). Even in relatively remotes parts of the US you can typically stick out your thumb and catch a ride to the next town pretty easily. I have done that a couple times and have ridden with others who did it a lot more and I think the longest wait for a ride was 20 minutes.
I'd suggest that you shoot for 20 pounds or less and for sure stay below 30 pounds or gear. You can usually buy food daily so don't need to carry much.
If you are at all inclined toward going a bit minimal on the gear I suggest going really light 10-15 pound gear weight is fairly easy to achieve and I have not found any great loss of comfort or convenient.
I have done long and longish tours with loads ranging from 45 pounds down to 11 pounds or so (not counting food or water). I found the lighter loads, lack of stuff to sort through and keep track of, and just simplicity of living with very limited items to deal with to be a joy. I was able to maintain cooking and camping capability and comfort just as well with the lighter loads.
BTW, there are other choices besides a trailer or panniers. Stuff sacks strapped on work well with lighter loads and there are also rackless "bikepacking" systems available if you are so inclined.