Your trainer level is already high enough for Machamp and Aerodactyl, maybe Onix if you have a couple WF/HP Kyogres. Remember that your trainer level doesn't mean shit if you don't have Pokemon powered up to it - a level 30 that's been carried and hasn't powered up anything is likely to only be as effective as someone in the mid-20's.
You pretty much answered your own question, dropping a lucky egg and trying to nail 3 T5 raids under its effects is the quickest way. Luckily you can now drop them in the raid lobby to buy a couple minutes squeezing raid #3 in. EDIT: You can also evolve things as you're walking/being driven from one raid to the next to squeeze a little more out.