The accounting hold is used to verify, before shipping, that funds for payment are available. The time this step takes is determined by the policies you've established concerning payment methods, be they personal checks, money orders, or other forms. Each payment method calls for its own timeline. For each method, add X number of days to the delivery date - and, again, communicate this to the customer on your site. Include the fact that money orders are processed immediately on receipt.
Credit cards add no time.
Shipping time estimates can be provided by your carrier, whether it is the U.S. Postal Service, FedEx, UPS, or another one. Shipping time will change depending on the time of day the order is picked up, type and weight of cargo, destination, or special handling requests. Be aware that some carriers consolidate freight overnight, which will add to the shipping time. And air freight typically must be received by the airline the day before flight departure. Most carriers will have a cutoff time for all pickups, meaning that you should figure in a pickup time window of one or more hours.