A new boiler front is certainly a possibility; these can be found in Lionel's Replacement Parts (see Support on website), plus eBay is a good source of this kind of part. Don't shy away from Lionel Postwar pieces, as some of those smokebox fronts were actually well-modeled, are available and can be improved (better handrails, etc).
Of course, the diameter needs to match, and the mounting methods vary; often the headlight is not included. Depends. It's a journey, but I've done it more than once.
The advantage of attacking the original one is that it almost certainly will still mount the factory way, and is certainly the right size. I would recommend getting another one of the same part, if possible, in case you butcher it. Not criticism - just experience - as failure is always an option.