In reply to JonnySchofield:
I'd recommend the Haute Maurienne. Good snow in the spring and relatively uncomplicated glaciers. Suggested route below:
Bonneval sur Arc - Refuge Carro. Could also take in Levanna Occidental / Aiguille Grand Rousse too if you start early. There is an avalanche prone slope on the approach which faces SE so worth an early start if there is avalanche risk.
Carro - Refuge Evettes via Col de Trièves. It's possible to take in other peaks too along the way. Col de Trieves is avalach prone
Refuge Evettes to L'Albaron then down to Bonneval or alternatively down to the Averole refuge and do another tour from there. The descent down to Bonneval is great but there is a narrow 40 degree section which has seracs way above it so worth taking care there. As i understand it the descent to the averole is more straightforward.
It's a classic route. But when we did it in good weather in April a couple of years ago there were very few others on it and reservations were not an issue in the huts. Huts are also much cheaper than Switzerland c. 50 euro half board at most.