Laptop touchpads (aka internal mouse) SUCK! My cursor jumps all over the place as the palm of my hand brushes the touchpad while I'm trying to type, but when I want to use the touchpad as a mouse, half the time it doesn't work. External wireless keyboard and mouse are the only way to go. Neither are ergonomic, not at home or at work, although I do use pull-out keyboard trays, which keeps the top of my desk free for paperwork or food.
BTW, learning to mouse with your non-dominant hand is a good exercise for your brain and it's a lot easier than learning to brush your teeth with your other hand. After more than ten years of teeth-brushing with my left hand, I find it's still more awkward than with my right hand, but mousing became 100% ambidextrous for me in almost no time. Let's see - almost 50 years of brushing my teeth vs. less than 10 years of mousing before switching hands...