It depends on how complicated the estate is and in which state the estate occurs.
Several states have simplified legal procedures and processes for small or simple estates. If the executor is reasonably smart and persistent and asks for help from the court, they could do that themselves. Especially if they've dealt with an estate or been exposed to the estate process before. They could certainly read your will and if it's decently written they would have a very good idea of what your wishes are.
If the estate is large or complex, then I think hiring a lawyer to help walk the executor through the process seems reasonable to me. Things like filing court documents, requesting letters testamentary, publishing the notice to creditors, calculating the estate value, filing the final individual and estate tax returns, and doing more complicated things like selling a family business or doing a TEDRA agreement are things I would leave to the professionals (attorney and CPA). Things like getting copies of the death certificate, filing for life insurance, distributing assets to the beneficiaries, and other similar activities, as well as funeral arrangements and obituaries and grave markers and taking care of personal property could pretty easily be done by the executor themselves I think.