Toe clips are a good idea to maximize power. Plus on a tricycle you can leave your feet attached to the pedals and remain upright when you stop (whereas on a bike you will fall over).

On the flip side, regarding gears and hills, it is best to keep tricycles on relatively flat terrain and to watch your speed carefully to avoid tipping over -- unlike bikes it is much more difficult to take turns at high speed safely. So the gearing that comes with most tricycles is probably best left as is to encourage safe riding.

Cheers,
Tim Oey

Adult tricycles are a great idea. I am in the process of converting a trike,that I received for free, to electric assist. I have started researching front wheel hub motors which I believe to be ideal for any type of bike for folks that like a little exercise but need a little help also. I have noticed that trikes can be found fairly inexpensive @ yard sales, and,yes they can be tricky when trying to turn too sharp. Good luck.

i have a small-ish adult trike. it folds in half and will go into the hatch back of my car. as a sort of sport model it has a shorter than standard distance between front and back wheels. be prepared with this size to smudge the back of you calf occasionally moving it around. my trike is less grandmotherly than most. it has upright handlebars and a cushiony seat (but not a giant tractor-type sit-down). it is almost dainty looking with its smaller than standard wheels.
that said, mine has an electric hub motor. i can pedal it on flats, but the 3 little 12 volt batteries and the motor make it heavy. around town it goes about 10mph and can go 15+ miles on an overnight charge. other configurations are possible.i like it very much and use it regularly for errands. it came with a back basket between the rear wheels and i added a removable shopping basket in front. i too have balance problems. getting out of toe clips at an intersection was always and invite to fall. the trike took care of that. as for hills, it's not going up that is the problem. after all, you can use the motor and pedal assist if need be. remember that a steep downhill is beyond the capability of the brakes, esp with the added weight of groceries or packages. JUST GO SLOW!
ride any likely trike you find. you really shouldn't catalog order a model you have never ridden. look for models with spring front fork and seat. most can be retrofitted with a motor if you decide to go that way.
good luck in your search. hope you enjoy yours as much as i do mine.
blessings,
emmer

There are a myriad of trike manufacturers out there, as there are configurations. Uprights, deltas, tadpoles, recumbents, velomobiles, faired, naked. Too many websites to list. Lightest are the sports trikes. There are a range of electric assist options available. The Australian manufacturer Greenspeed makes a delta and range of tadpole trikes including folding or collapsable. Varna do a good handcycle trike.

I rode a recumbent trike for about 7 years (most of those years sans car), and for the last 3 years I have been on a recumbent bike.  Without a doubt, I much prefer the trike; despite the extra weight, it is feels much safer to ride in the city as I don't have to focus any attention on balance, and drivers give me more room as I am clearly three dimensional.  I never found hills to be any more of a problem than on the bike, as long as you have good low gears.  And it's fun... my bike mechanic once called it a "Ferrari."

You should definitely check out the recumbent trikes, as there are a wide variety of different styles and much better gear ranges and equipment than most upright trikes.  The brands I can think of off the top of my head are Catrike, ICE, Greenspeed, Lightfoot, HP Velo, and Wizwheels.

But, as much as I am a recumbent enthusiast, the most important thing is to get something that you'll be happy riding... and get out there and ride!

I first purchased a Lightfoot trike in '99 and haven't looked back. We are now a no-car multi-trike family. We also have a 4-wheel side-by-side tandem that serves as the 'family car'. One trike is equipped with electric assist. All bikes are from Lightfoot Cycles and the width works well in traffic.
I even tow a riding lawn mower trailer I purchased from Home Depot and am able to carry lumber drywall and other building supplies. The trailer also doubles as a float to use in various parades I enter.

My husband's been looking for mountain bikes and accessories on Craigslist lately and there was an adult tricycle available on there the other day.

That would be an excellent place to start, if you're wanting one.  

For some weird physical reason, which no doubt Archimedes, or some other clever lad way back then who was good with his conjugations and declensions, already figured out, you need to turn really generously and patiently on a tricycle.  So if your idea of coolness involves speed, then trikes are out.

On the other hand, just hang an image of Avalokiteshvara from the handle-bars, or Dionysus with tigers if that is more your style, and you have nothing to worry about.