We applaud you for making retirement savings such a priority. The company I work for is selling and we will get our profit sharing assets after the sale closes. The first thing you should do is roll the profit sharing plan assets into an IRA rollover. That way you will keep the tax deferred nature of the funds intact and can continue to keep that money earmarked for retirement. How you invest the money depends on how much you have to invest and your return objectives and risk tolerances.
Mutual funds are a great idea, in that they provide professional management and diversification.
Depending on how much you have to invest, you might also consider looking for a professional money manager who will manage your money in a manner consistent with the way you want your money managed. Keep focused on your long-term retirement objectives. Maintain the tax-deferred status of your retirement funds and invest in a manner most suitable for your objectives. Unlike traditional IRAs, your contribution is not tax deductible. Like other IRAs, however, your assets grow tax deferred, and if held in the Roth IRA for at least five years, you can withdraw the money after age 59 with no taxes due.