Winter routes depend largely on conditions-in particular the avalanche risk, but here are my suggestions.
Snowshoeing, according to conditions, needs no practice
you to walk along paths without sinking to your knees or
slipping on frozen snow(the snowshoes have small crampons
on the underneath). In early and late winter,they often
aren't necessary as the paths are free of snow.
I would also be happy to spend an afternoon teaching teenagers to build a proper mountaineers snow shelter. We can also observe in the snow tracks of snow-hare, deer, ibex, squirrel and even wild-boar.
A gentle descent of the valley from Argentiere to Chamonix passes the hamlet of Les Grassonnets with one of the last working farms in the valley along a plateau, before entering alpine forest emerging in the village of Les Bois-completely under the glacier as recently as 200 years ago-and then arrives in Chamonix conveniently near a number of cafes and bars...
A tour from Les Houches to Vaudagne takes us through forest and and the summer hamlet of Charousse, across its pastures down to Vaudagne village where we can visit the donkies of la Compagnie des Anes, used for trekking and children's rides in summer, and the tiny chapel with its alpine decorations in the interior, before returning to Les Houches.
Both these routes are outside any avalanche threat, and can be done under almost any conditions.
A descent of the valley of Vallorcine is normally possible, starting from L'Auberge de Boern, an original farmhouse serving traditional lunches by prior arrangement and often only accessible on snowshoes through the snow.
Ascent is more tiring - for a medium grade I can recommend following the summer tram line from the ski area of Les Houches through forest, the return along the crest of the ridge through forest; we may find ibex tracks and droppings.
Also medium difficulty, an ascent above the village of Servoz through the wild forest-much thicker then Chamonix due to lower altitude and increased exposure to sunshine.
For the fit and adventurous, I would enjoy taking you higher to Aiguille des Posettes above the Le Tour ski area, or Les Chalets de Loriaz above Vallorcine.
I also like the wild high snow plateau accessible from Les Contamines with the possibility of ascending a summit with a huge vista, a short drive out of the Chamonix valley. It is possible to climb a broad track above Cordon to a wide ridge, rarely visited in winter, and with amazing views of Mont Blanc.
These are wild high mountain routes and should be taken seriously in terms of preparation and evaluation of conditions. You may need to pay for a lift ticket also.
As well as snowshoeing I can also teach use of avalanche transceivers, poles and shovels - all three are necessary together - and construction of snow-shelters; kids might enjoy constructing one somewhere to have lunch in.
I can also arrange husky sledging.
My French partner, an experienced tour guide, can offer excursions to the world famous art gallery at Martigny in Switzerland, the Baroque church trail or the hot baths of Saillon in the snow, and a visit to the mediaeval walled village of Saillon and its wine cellars. She is available on the same dates as myself.