We are currently equipping a boat for long-term (five years, we hope) cruising and we face these questions every day. Capacity isn't so much an issue as it's a steel full-keeler of some 40 feet on deck, 42 LOA. We are going for some complexity in the energy-self-sufficiency department because we'll have a child aboard, and I write for a living, necessitating some way to stay in touch offshore to run in a minor way my business and to transmit and receive educational materials for our kid.
We will also be renting out the house as two flats, and while I will assign to a manager the general landlording duties, I will have to approve expeditures, file house taxes, monitor utilities, etc.
Generally, we are moving into a fairly rarefied subset of cruisers: the anchoring-out, lone wolf types, and the equipment list is reflecting this.
Stuff we won't have: Air conditioning on the hook, a diesel genset, a fully electric windlass, a RIB, a 9.9 HP outboard, cockpit lockers, huge alternators, bow thrusters, electric winches, davits, two heads, dedicated nav displays, satphone.
Stuff we will have/already have: Espar heating for offshore, Mermaid A/C plus heat if we are on shore power; a Honda gas genset, a custom arch for comms, shade and 3 or 4 large solar panels; 4 x 8D AGMs; wind generator that can be towed, like a Duo-Gen; two tenders (Portabote and nesting dinghy) stowed on deck; small workshop forward; 2000 W inverter/charger; foot pumps for water; only one head; PC-based nav display; extensive fuel filtering, a separate polish tank; new water tanks; manual-optional windlass; four anchors; multiple rodes; feathering prop, large inventory of spares.
The idea is to stay independent of the shore when desirable in order to reduce costs. I don't object to tying up in a marina now and then, but it runs counter to our ideals of self-sufficient cruising. I would rather get more months of zero-sum cruising (the house rental will pay down the mortgage, the utilities and probably my diesel bills, and I can afford $25K/year for our trip, which is plenty if I'm not eating ashore every night) than to have a gold-plated trip. We may haul out for a season in New Zealand to put our boy in school and do maintenance halfway through our trip.
Beth Leonard's "Voyager's Handbook" is very good at laying out the different styles of cruising: the totally budget "do it now with what you've got" idea all the way to the high-life style found in the Caribbean. Our boat, and our plans, are more "Ocean Navigator" oriented, because we intend to go off the beaten track a little farther...we haven't ruled out high-latitude sailing as the boat is built for it.
Anyway, that's where we are now: making complex adjustments in order to have a simple life aboard.