Of course I'd want the job today..! But with a caveat:
100 acres is large, I'd require permission to sell 40 - 45 acres (picking the oldest, most dilapidated half, with no critical buildings) which, given the zoo's location should provide enough money for renovations and construction to a high standard for the remainder of the zoo...
By referring to this map:
http://www.sfzoo.org/openrosters/DocDownload.asp?id=28924
You would have to keep the left side of the zoo as it has the majority of the buildings and new exhibits plus the strip of land across the top including the rainforest and Grizzly Gulch (which would also keep the secondary parking and a second entrance could be created)... The rest of the land to the right of the Gorilla reserve following a line of to the chimps, koalas, the rainforest building, down to Grizzly Gulch could be auctioned off to approved bidders (say someone who is looking to develop a convention centre or theatre... The zoo would lose a lot of hoofed stock but the only iconic species it would lose would be the lions and tigers (which needed a new exhibit decades ago), Rhinos and the penguins...
With the money I'd expand the African section to include lions and black rhinos, renovate and expand all the African primate exhibits and maybe renovate the discovery centre itself, the upper half of the zoo would be largely developed into an Asian forest theme tearing down parts of the children zoo and moving that to the top left corner leaving the insect zoo and expanding on the small native American animals area... The theme of the Asian forest could be from rainforest to highland (as to include the zoo's Siberian tigers, snowleopards, which I can't see on this map, as well as the Asian rhinos which they wouldn't want to lose)... I'd want to lose the penguins as an exhibit...
All buildings at minimum to be given a fix up and uniform look and at maximum completely gutted to form part of a streamlined plan, a new medical centre to be built in a redundant building or built from scratch and the entrance plaza should have the souvenir shop as the exit, i.e. you must leave through the gift shop and the zoo should find a prominent position within the zoo with a view to build an excellent restaurant which can be accessed from both inside and outside the zoo and is open after hours, the South American hall to be expanded to include the zoo's tapir and anteaters and finally the old bear pits to be torn down and large north American animal exhibits could be developed...
The Zoo would then have the following distinct areas:
African Trail
Lemur Forest
Asian Trail
Children's zoo, Small Native American Animals and Insect Zoo
South American Tropical Forest
Large Native American Animals
Along with uniform buildings each area should have decorative signage themed to area but similar throughout the whole zoo, landscaping should be a top notch so the zoo has style not just new exhibits... New exhibits should be carefully researched to find similar exhibits which are great for the animals, visitors, keepers, aesthetically pleasing but also relatively cheap to construct (stretch the money)...
If there was any left over money it could go into a investment trust with half the profits going to zoo running costs and half back into the fund...
Just a hypothetical but fun to think about...