I had a T100 for a long time and did some offroading, and only rarely felt I needed more clearance (only once or twice on trails I really shouldn't have been on). The thing sits higher than some lifted trucks, so I wouldn't worry about a lift at first unless you know for certain you'll need one. The other issue is that because of the torsion bar front suspension, you're pretty limited in terms of aftermarket suspension options. I think there are some beefed up torsion bars you can get or a ball joint spacer kit. Other than that there's not much unless you go long travel. The rear leaf packs are pretty robust so I'd be surprised if you need new ones...you may just need shocks.
I would focus on baselining it and getting the front suspension and steering in order. New ball joints, new sway bar bushings and end links from Energy Suspension, rebuild the idler arm, replace the steering damper, new shocks at all four corners (KYB Gas-A-Justs or Bilsteins are some of the best choices) and ensure all the drag link ball studs are in good shape. Slap on some Aisin hubs from an IFS pickup or 4Runner, and you'll be in good shape. Check the CVs too...they spin all the time stock (the Aisin hubs allow them to be disconnected). If you really want to make the steering robust, you could throw on the Total Chaos idler arm.
Make sure the timing belt is new, and replace it if not (while you're doing the seals). Plugs would also be good, and ensure they are the correct Denso or NGK dual electrodes (plugs really woke my truck up). I would also plan to replace all diff, trans, and tcase oils, and make sure the rear axle housing isn't cracked at the spring perch welds. Then throw on some good A/Ts and have fun.