I've owned and hunted with 8 crossbows over the last 20 years, I also started a few nieces hunting with crossbows, and here are my recommendations.
A crank cocking device is nice, but if you or another adult are going to be with them anyway, you will probably be the one cocking the crossbow. Models with any cocking winch integral to the bow is likely to be hundreds more in cost, so in this case, simple may be better.
Something short, light and with decent speed at a relatively low cost is what you need. Try to find something with speeds over 350fps, so that there is very little chance of the deer jumping the string, and distance/trajectory errors aren't as critical.
For a standard layout crossbow, the PSE Fang is decent. Another standard crossbow is the Wicked Ridge invader.
For a reverse limb, a Wicked Ridge RDX 410 is a winner. Right now Midway has them in stock at a huge discount. I'd jump on this if you want a good reverse limb bow. BTW Wicked Ridge is Ten Points discount brand without the expensive add ons.
The Wicked Ridge RDX 400 hunting crossbow is a perfectly balanced reverse-draw crossbow measuring only 9-inches wide and shooting up to 400 FPS. The RDX...
www.midwayusa.com
My current crossbow is a Scorpyd at nearly 500 fps, but I've got over $2500 in that bow.