Low voltage for your gate opener will have to be separate wires from your low voltage lighting. The reason they have to be separate wires is the transformer for the gate opener is specifically designed to be the right output for the control board of the gate opener. Low enough to not burn the board yet high enough to effectively charge the battery or run the gate opener. If you tire dot borrow power for the lights it would make the batteries charge too slow or the gate opener unintentionally obstruct. If you tired to increase the output of the transformer to effectively feed both the lights and gate opener, if the lights were ever no absorbing the extra amperage this would be too much for the gate opener to handle and would burn your control board. So to do this most efficiently use a shovel or hoe and make a narrow V shape trench in the ground from the outlet to the gate and the end location for the lights. Purchase direct burial low voltage wire for both the gate opener and lights. Please see the specified gauge for each from the instructions for the lights and the gate opener. Lay both runs of wires in the bottom of the V shape trench and step on the top of the hole to close the V shape trench back in on top of the wires. the best outlet to use is one in your garage because the outlet will need to be covered. It is also smart to use a surge suppressor at the outlet and an in line surge suppressor at the end by the gate opener control board as long runs of wire under ground can attract surges. Use a piece of conduit where the wires protrude from the ground at both ends. This will help protect the wires from being damaged when doing lawn maintenance (ie a weed whacker or lawn mower cutting the wires). Then make your connections to your gate opener and your lights and also to the transformers on the other end at the outlet according to the instructions of both devices.